The investigation, conducted by Amnesty and Airwars, "gives a brutally vivid account of more than 1,600 civilian lives lost as a direct result of thousands of US, UK and French air strikes and tens of thousands of US artillery strikes in the Coalition’s military campaign in Raqqa from June to October 2017," the release said.
READ MORE: Largest Mass Grave of Daesh Victims Discovered in Syria's Raqqa — Watchdog
The rights group called on the US-led coalition to end its two years of denial and acknowledge the devastation caused by its campaign against the Daesh terrorist group in Syria.
“Coalition forces razed Raqqa, but they cannot erase the truth. Amnesty International and Airwars call upon the Coalition forces to end their denial about the shocking scale of civilian deaths and destruction caused by their offensive in Raqqa,” said Chris Woods, the director of Airwars.
The two groups said their investigation documented incidents that amount to violations of international humanitarian law.
They also called on the coalition to compensate families and fully investigate what went wrong in Raqqa to avoid repeating the same mistakes in any future military operations.
In turn, Joint Task Force-Operation Inherent Resolve (JTF-OIR) said that US-led forces have killed at least 1,291 civilians while battling the Daesh terrorist group in Syria and Iraq over the last four and a half years.
"At least 1,291 civilians have been unintentionally killed by Coalition strikes since the beginning of Operation Inherent Resolve," the assessment said.
In March, the Joint Task Force carried over 146 civilian-casualty allegation assessment reports from previous months and received seven new ones. Of the 31 reports it reviewed, the Joint Task Force determined that 11 were credible, revealing 34 unintentional civilian deaths.
"One hundred and twenty two reports are still open, including three that had been previously closed, but were reopened due to the availability of new information," the Joint Task Force said.
The United States and its allies have been fighting Daesh* in Syria since 2014 without the approval of the Syrian government or a mandate from the UN Security Council.
The city of Raqqa first fell into the hands of Syrian opposition forces in 2013 and was then captured by the Daesh terrorist group, which declared the city its capital.
The military campaign to recapture Raqqa was launched in June 2016 by the Kurdish-led Syrian Democratic Forces (SDF) backed by the US-led coalition. The operation culminated in the 2017 Battle of Raqqa, which eventually allowed the SDF to gain control over the city.
*Daesh (also known as ISIS/ISIL/IS) is a terrorist group banned in Russia