All Syrian sides that fought in the battle for Aleppo committed war crimes and the deal to evacuate civilians following the opposition defeat was a "crime of forced displacement", a UN probe said Wednesday (March 1st).

The UN Commission of Inquiry (COI) for Syria documented violations including chemical attacks and civilian executions perpetrated during the regime's five-month siege of eastern Aleppo, which had been a key opposition stronghold, AFP reported.

From July 21, 2016 to December 22nd, when government troops recaptured the city, the Syrian air force and its allies "conducted daily airstrikes" on Aleppo, the COI said.

There is conclusive evidence that Syrian aircraft dropped "toxic industrial chemicals, including chlorine", the report said.

The aerial bombardments saw hospitals, markets and residential buildings repeatedly hit.

In a major new finding, investigators also said there was proof that Damascus was responsible for September 19th airstrikes in Aleppo that deliberately targeted a humanitarian convoy, killing at least 10 aid workers.

The Syrian government has fiercely denied responsibility for the bombardment in Urem al-Kubra and a separate UN probe in December said it was impossible to establish blame.

Investigators described Aleppo as a scene of "unrelenting violence" in which civilians in the opposition-held east and government-controlled west fell "victim to war crimes committed by all parties".

The disparate opposition factions in Aleppo, including al-Nusra Front, now known as Fatah al-Sham Front, shelled civilians in western Aleppo and indiscriminately fired with no clear military target, the COI said.

The evacuation deal agreed between warring parties and which allowed for civilians to move into western Aleppo or be transported to Idlib, left civilians with "no option to remain", the COI said.

"Such agreements amount to the war crime of forced displacement of the civilian population", UN investigators concluded.