March 1 (UPI) -- Both sides in the battle for Aleppo in Syria last year committed war crimes, according to a United Nations investigation released Wednesday.
The Independent International Commission of Inquiry blamed Syrian and Russian forces on one side and the U.S.-led opposition on the other side for attacks in Aleppo from July until the city was re-captured by the Syrian government on Dec. 22.
Aleppo, once Syria's largest city, had been divided into rebel and government parts since 2012.
Most notably, the report described the "deliberate" bombing of a humanitarian convoy by the Syrian government that killed 14 aid workers. President Bashar al-Assad's government has fiercely denied responsibility for the convoy's bombardment and a separate U.N. investigation in December said it was impossible to establish blame.
The report also said Syrian and Russian forces had launched indiscriminate "daily airstrikes" with cluster munitions on the rebel-held eastern part of Aleppo. Hundreds of people were killed and hospitals destroyed.
The report said Syrian helicopters used banned chlorine bombs on Aleppo "throughout 2016," causing hundreds of causalities.
On Tuesday, Russia and China vetoed a U.N. sanctions resolution against the Syrian government.
Investigators could not assign blame for various attacks in Aleppo.
"Throughout the period under review, the skies over Aleppo city and its environs were jointly controlled by Syrian and Russian air forces ... (They) use predominantly the same aircraft and weapons, thus rendering attribution impossible in many cases," the report said.
Opposition groups killed and injured several dozen people in government-controlled western Aleppo. They also prevented civilians from leaving eastern Aleppo and used them as "human shields." They also attacked a Kurdish residential district, the report mentioned.
U.N. investigators noted the U.S.-led coalition didn't attack Aleppo from the air in the second half of 2016.
The findings are based on 291 interviews with victims and witnesses, and also on forensic evidence and satellite imagery.
The report was issued as Syrian peace talks continue in Geneva, Switzerland.