The grim conclusions, based on more than 500 interviews, coincided with reports of heavy civilian casualties in the Damascus suburb of eastern Ghouta, where Syrian and Russian forces pushed on with a ferocious offensive aimed at crushing the last major rebel stronghold in the area.
Airstrikes and shelling there on Monday killed 94 civilians, according to the Union of Medical Care and Relief Organizations, based in France. They also forced an aid convoy, the first to reach the enclave in over three months, to leave before it had fully unloaded.
United Nations investigators had previously reported Russia’s critical role in the war in the two years since it stepped in to rescue of President Bashar al-Assad’s faltering army, but a panel member, Hanny Megally, said this was the first time the commission had been able to nail down Russian involvement in a specific incident.
The panel cited evidence from early warning observers in Syria, who tracked the fixed-wing aircraft from the Russian air base at Humaimim, 100 miles from Al Atarib, until its attacks in the early afternoon, when the town’s market was crowded with people who had left work.
The panel also rejected the United States-led coalition’s account of multiple airstrikes last March on a school building in Raqqa Province, which investigators said killed at least 150 of the 200 civilians who were housed there after fleeing fighting elsewhere. The panel said it had found no evidence to support the coalition’s claim that the school was occupied by Islamic State fighters.
The coalition attack did not amount to a war crime because it had no intent of hitting a civilian target, the panel concluded, but had violated international law by failing to take adequate precautions to protect civilians.
The international coalition had also inflicted countless civilian casualties in daily airstrikes on Islamic State fighters in the city of Raqqa, launching attacks even though the militants were using civilians as human shields, the panel said.
The commission also faulted the coalition-backed Syrian Democratic Forces over their internment of some 80,000 civilians who had fled the fighting around Islamic State strongholds in Raqqa and Deir al-Zour to vet them for possible links to the jihadists.
They continued to keep thousands of internally displaced people in camps, investigators said, including women, children and the disabled, in what the panel said amounted to arbitrary and unlawful detention.
After six and a half years collecting evidence, commission members said on Tuesday that they planned to work vigorously on behalf of the victims but emphasized “there can be no trade-off between justice for the victims and a viable political solution” to the conflict.
The panel will present its findings to the Human Rights Council in Geneva next week and urged it to “ensure that there are no pardons or amnesties for those responsible for ordering or carrying out gross human rights violations and committing international crimes.”