Iraqi and coalition forces fighting Islamic State (IS) militants in the city of Mosul used unnecessarily powerful weapons, an Amnesty International report says.
They deployed heavy weapons in densely-populated areas, Amnesty says.
Coalition officials have so far not commented on the allegations, but they have previously insisted they have done all they could to protect civilians.
IS fighters are also accused by Amnesty of committing serious abuses.
The militants are accused of using human shields during coalition attacks and of summarily killed hundreds - possibly thousands - of civilians, leaving bodies to hang from electricity pylons as a warning to others.
Citing an eyewitness, the Amnesty report The Civilian Catastrophe in West Mosul says that bombardments by Iraqi and US-led coalition forces have killed a "huge number" of civilians.
The report calls for the formation of an independent commission to investigate the number of civilian deaths.
It examined hostilities in the west of the city from January to mid-May and accuses coalition forces of failing to adapt their tactics even when it was clear that IS militants had forced civilians into areas most likely to come under attack.
They used "imprecise weapons with wide-area effects in densely-populated urban environments", the report says, and subjected them to a terrifying barrage of fire.
The use of human shields by IS "does not lessen the legal obligation of pro-government forces to protect civilians", Amnesty's Middle East Research Director Lynn Maalouf said.
Amnesty allegations against Iraqi and coalition forces
They carried out a pattern of attacks which "appear not to have struck their intended military targets, instead killing and injuring civilians"
Some civilian deaths and injuries appear to have resulted from an inappropriate choice of weapons or a failure to take necessary precautions to verify a target
On 17 March a US airstrike on Mosul's al-Jadida neighbourhood was carried out to kill two IS snipers - but also killed more than 100 civilians
The UK government's claim that hundreds of RAF air strikes in and around Mosul have resulted in no civilian casualties "is at best implausible"
Amnesty allegations against Islamic State forces
They carried out a systematic campaign of forced displacement in the Mosul area, moving thousands of civilians from neighbouring villages to be used as human shields
They trapped people inside their homes by welding doors shut, rigging booby traps at exits, and summarily killing hundreds - perhaps thousands - of people attempting to escape
One witness described how militants hanged the bodies of civilians trying to flee from electricity pylons
"If you stayed, you would die in your house from the fighting," the witness said, "[but] if you tried to run away, they would catch you and kill you"
Colombia's President Juan Manuel Santos has signed a decree granting amnesty to another 3,600 members of the Farc rebel group, which last year reached a peace deal with the government.
It is the third and final amnesty decree signed by Mr Santos.
More than 7,000 rebels in total have been granted amnesty or released from prison as part of their reintegration into Colombian society.
Last month the Farc completed its disarmament process.
The rebels handed all its 7,000 registered weapons to the United Nations mission in Colombia.
Earlier on Monday, the United Nations Security Council voted to set up a new mission in the country, which from September will oversee the implementation of the peace deal.
The move puts an end to more than five decades of conflict.
The Marxist rebel group was found in 1964 to defend the rights of landless peasants.
It entered formal peace negotiations with the government in 2012. The talks were held in Cuba and lasted four years.
The final agreement was rejected by the Colombian people in a referendum last October. But a reviewed version was approved by Congress a month later and signed into law.
The Farc has agreed to give up its armed struggle to become a political party.
A key part of the agreement was the rebels' reintegration to civilian life. It was agreed that all Farc members who did not commit serious crimes would be granted amnesty.
The three decrees signed by Mr Santos have benefited 6,005 former rebels. Another 1,400 who were serving prison sentences have been released in the past few months.
Mr Santos won last year's Nobel Peace Prize for his peace efforts.
Following the success of the Farc negotiations, Colombia's second rebel group, the National Liberation Army, or ELN, also entered formal peace talks. They are being held in neighbouring Ecuador.
Seven Hindu pilgrims, six of them women, have been killed in a militant attack in Indian-administered Kashmir after their bus apparently got caught in crossfire.
The bus is understood to have been returning from the Amarnath Cave pilgrimage site when militants launched an attack in Anantnag district.
It is thought the target was vehicles at a counter-insurgency base.
The attack, which also left 19 pilgrims wounded, could raise tensions.
A police source told the BBC the attack did not appear to be aimed at the bus, but hardline Hindu groups linked to Prime Minister Narendra Modi's ruling party have long wanted to see tough action against the armed revolt against Indian rule in the Muslim-majority region.
News of the attack has already sparked anger on social media, with people demanding immediate retaliation on behalf of the pilgrims, most of whom came from Gujarat, Mr Modi's home state.
Mr Modi tweeted he was "pained beyond words", adding: "India will never get bogged down by such cowardly attacks and the evil designs of hate."
The attack has also been condemned by separatist leader Syed Ali Geelani, whose spokesman called it "an act of terror", while outlawed armed group Lashkar-e-Toiba distanced itself from the attack, saying "it was aimed at bringing a bad name to the Kashmiri movement".
Meanwhile, Chief Minister Mehbooba Mufti, who stayed overnight with the wounded, all of whom were out of danger, promised that her forces "would not spare" those involved.
The attack comes after some hardline separatist leaders said they welcomed the pilgrims - about 100,000 of whom have already completed the journey - as their fight is not with ordinary Indians.
One police source told the BBC the bus was not properly registered, and should have been off the road by the time of the attack, at 20:20 local time (14:50 GMT) on Monday.
President Donald Trump's son has hit back at US media reports of his meeting with a Russian lawyer who said she had damaging material about Hillary Clinton.
Donald Trump Jr denied issuing inconsistent statements about last year's meeting.
He also suggested it was normal practice to receive information about a political opponent.
US officials are investigating alleged Russian meddling in the US election.
The president's son-in-law, Jared Kushner, and then-campaign head, Paul J Manafort, were also at the meeting with Natalia Veselnitskaya.
Mr Trump Jr insists she provided "no meaningful information" on Mrs Clinton, his father's rival for the presidency.
On Monday he tweeted sarcastically: "Obviously I'm the first person on a campaign to ever take a meeting to hear info about an opponent."
He then tweeted: "No inconsistency in statements... In response to further Q's [questions] I simply provided more details."
Later, Mr Trump Jr tweeted: "Happy to work with the committee to pass on what I know", after a Republican member of the Senate Intelligence Committee said it should interview him.
The White House says there was nothing inappropriate about Mr Trump Jr's meeting with the Russian lawyer.
When was the meeting and how did it come to light?
It took place on 9 June 2016 at New York's Trump Tower, just two weeks after Donald Trump secured the Republican nomination.
It is thought to be the first confirmed private meeting between a Russian national and members of President Trump's inner circle.
After the New York Times first reported the meeting on Saturday, Mr Trump Jr released a statement which confirmed that it had taken place but did not mention whether it was related to the presidential campaign.
However, another Times report, on Sunday, said Mr Trump Jr had agreed to the meeting after being offered information that would potentially prove detrimental to Mrs Clinton.
The paper cited three White House advisers briefed on the meeting, and two others with knowledge of it, as its sources.
Mr Trump Jr said that an acquaintance he had known from the 2013 Miss Universe pageant had set up the meeting. The Washington Post said that figure was music publicist Rob Goldstone, who has links to the Russian music industry.
In a statement on Sunday, Mr Trump Jr said he had been asked to meet "an individual who I was told might have information helpful to the campaign".
"I was not told her name prior to the meeting. I asked Jared [Kushner] and Paul [Manafort] to attend, but told them nothing of the substance."
What was discussed at the meeting?
Mr Trump Jr's statement continues: "After pleasantries were exchanged, the woman stated that she had information that individuals connected to Russia were funding the Democratic National Committee and supporting Mrs Clinton.
"Her statements were vague, ambiguous and made no sense. No details or supporting information was provided or even offered. It quickly became clear that she had no meaningful information.
"She then changed subjects and began discussing the adoption of Russian children and mentioned the Magnitsky Act.
"It became clear to me that this was the true agenda all along and that the claims of potentially helpful information were a pretext for the meeting."
Ms Veselnitskaya said on Saturday that "nothing at all was discussed about the presidential campaign" and insisted she had "never acted on behalf of the Russian government and have never discussed any of these matters with any representative of the Russian government".
What is the Magnitsky Act and who is Natalia Veselnitskaya?
Adopted by Congress in 2012, the act allows the US to withhold visas and freeze financial assets of Russian officials thought to have been involved in human rights violations.
It is named after a Moscow lawyer, Sergei Magnitsky, who had accused Russian officials of tax fraud but was himself arrested and died in police custody.
The US law so incensed President Vladimir Putin that he suspended a programme allowing Americans to adopt Russian children.
Mr Veselnitskaya is a lawyer whose clients include companies and individuals said to be close to the Kremlin and she has been at the forefront of a campaign - backed by the Russian state - to overturn the Magnitsky Act.
Russian presidential spokesman Dmitry Peskov insisted the Kremlin had no idea who she was: "We cannot keep a close watch on the meetings of all Russian lawyers inside the country and abroad."
Analysis: One piece of an unseemly puzzle?
Anthony Zurcher, BBC North America reporter
If it walks like collusion and talks like collusion... what exactly is it?
For the first time there appears to be direct evidence that three individuals in US President Donald Trump's inner circle met with a well-connected Russian prior to the presidential election where the campaign - including the possibility of damaging information about Democratic presidential candidate Hillary Clinton - was discussed.
Donald Trump Jr has denied that anything relevant came out of the meeting but that could be beside the point. Intent is key and this may end up just one piece of a particularly unseemly puzzle.
This is also troubling news for the two other principals involved - son-in-law Jared Kushner and campaign chair Paul J Manafort - who are both embroiled in their own Russia-related controversies.
In May the president insisted that he had not colluded with the Russians. "But I can only speak for myself," he said. Some in his administration may have swallowed hard at that line - and now three individuals, if the New York Times is right, are leaking dynamite to the press.
Try as they might, the Trump team cannot seem to escape this Russia-related vortex. It makes one wonder what grim reality spins beneath the surface, pulling everyone down.
How has the rest of the Trump team responded?
Mr Kushner and Mr Manafort have not commented, although Mr Kushner's lawyer said her client had previously disclosed the meeting on security clearance forms. Mr Manafort has disclosed the meeting to congressional investigators.
A spokesman for President Trump's legal team said on Sunday that the president was "not aware of and did not attend" the meeting.
White House chief of staff Reince Priebus said the meeting was a "big nothing burger".
The New York Times said Mr Trump Jr had told the paper in March that he had not met any Russian nationals to discuss campaign-related matters.
Why is Russia being investigated?
It is alleged that Russian hackers stole information linked to the Clinton campaign and passed it to Wikileaks so it could be released and help tip the election towards Mr Trump.
Congressional committees and a special prosecutor are investigating whether there was any collusion between the Trump team and the Russians.
The investigations have yet to reveal any evidence of collusion, something the president has always denied.
Last week Mr Trump said interference in the election "could well have been" carried out by countries other than Russia and interference "has been happening for a long time".
Iraqi Prime Minister Haider al-Abadi has formally declared victory over so-called Islamic State (IS) in Mosul.
Mr Abadi waved a national flag with troops after announcing the "collapse of the terrorist state of falsehood".
Earlier, clashes were reported in a small part of Old City where a few dozen IS militants were holding out.
The battle for Mosul has taken almost nine months, left large areas in ruins, killed thousands of civilians and displaced more than 920,000 others.
Commanders from the US-led coalition that has provided air and ground support to Iraqi forces said the urban combat had been most intense since World War Two.
Mr Abadi made the declaration of victory at the operations room of the Counter-Terrorism Service, whose elite forces were the first to enter Mosul in November.
Using a pejorative term for IS based on an Arabic acronym of its former name, he said: "I announce from here the end and the failure and the collapse of the terrorist state of falsehood and terrorism, which the terrorist Daesh announced from Mosul."
But Mr Abadi warned that more challenges lay ahead.
"We have another mission ahead of us - to create stability, to build and clear Daesh cells.
"And that requires an intelligence and security effort, and the unity which enabled us to fight Daesh," he added, before waving an Iraqi national flag.
The US-led coalition confirmed that while areas of the Old City still had to be cleared of explosive devices and possible IS fighters in hiding, the Iraqi security forces had Mosul "firmly under their control".
The senior American commander in Iraq, Lt Gen Stephen Townsend, congratulated the Iraqi security forces on their "historic victory against a brutal and evil enemy".
"Make no mistake; this victory alone does not eliminate [IS] and there is still a tough fight ahead. But the loss of one of its twin capitals and a jewel of their so-called caliphate is a decisive blow," he said.
Mr Abadi had to delay declaring the "liberation" of Mosul on Sunday because a pocket of resistance remained in the Old City, on the western bank of the River Tigris, that was only about 180m (200 yards) long and 45m wide.
Iraqi army officers believed only a few dozen militants were left inside along with their wives and children, who they said were being used as human shields.
Gunfire and explosions were heard coming from the area earlier on Monday.
Mosul has been devastated by the battle, with the UN estimating that more than 5,000 buildings have been damaged and 490 destroyed in the Old City alone.
"It's a relief to know that the military campaign in Mosul is ending. The fighting may be over, but the humanitarian crisis is not," said the UN Humanitarian Coordinator in Iraq, Lise Grande.
"Many of the people who have fled have lost everything. They need shelter, food, health care, water, sanitation and emergency kits. The levels of trauma we are seeing are some of the highest anywhere. What people have experienced is nearly unimaginable."
IS militants overran Mosul in June 2014, before seizing control of large parts of northern and western Iraq. The following month, Abu Bakr al-Baghdadi made his first and only public appearance as IS leader at the city's Great Mosque of al-Nuri, and gave a speech proclaiming the creation of a "caliphate".
IS blew up the mosque almost exactly three years later as Iraqi troops prepared to retake it - a move Iraq's prime minister called a "formal declaration of defeat".
The BBC's Jonathan Beale in Mosul says the jihadists may have lost militarily in the city, but this is not their end in Iraq nor the end of their twisted ideology.
IS still controls territory in three areas of Iraq - around Hawija, 130km (80 miles) south-east of Mosul; around Tal Afar, 65km west; and from Ana to Al-Qaim in the Euphrates river valley, 250km to the south-west.
It also holds a string of towns along the Euphrates in Syria, including Albu Kamal and Mayadin, but its stronghold of Raqqa is besieged by US-backed fighters.