UN chemical weapons experts in Syria
UN chemical weapons experts in Syria Reuters

Syrian government forces have used chemical weapons more than two dozen times during that country’s civil war, including in April’s deadly attack on Khan Sheikhun, UN war crimes investigators have determined, according to a Reuters report published Wednesday.

A government warplane dropped sarin on the town in Idlib province, killing more than 80 civilians, the UN Commission of Inquiry on Syria said, in the most conclusive findings to date from investigations into that chemical weapon attack.

The panel also said U.S. air strikes on a mosque in Al-Jina in rural Aleppo in March that killed 38 people, including children, failed to take precautions in violation of international law, but did not constitute a war crime.

The weapons used on Khan Sheikhoun were previously identified as containing sarin, an odorless nerve agent. That conclusion, reached in July by a fact-finding mission of the Organization for the Prohibition of Chemical Weapons (OPCW), did not say who was responsible.

“Government forces continued the pattern of using chemical weapons against civilians in opposition-held areas. In the gravest incident, the Syrian air force used sarin in Khan Sheikhoun, Idlib, killing dozens, the majority of whom were women and children,” the UN report said, according to Reuters, declaring the attack a war crime.

Commission chairman Paulo Pinheiro told a news conference on Wednesday, “Not having access did not prevent us from establishing facts or reasonable grounds to believe what happened during the attack and establishing who is responsible.”

In their 14th report since 2011, UN investigators said they had in all documented 33 chemical weapons attacks to date.

27 of the attacks were carried out by the government of President Bashar Al-Assad, including seven between March 1 and July 7, the investigators determined. Perpetrators had not been identified yet in the six remaining attacks, they said.

Assad has denied using chemical weapons and has even claimed that the Khan Sheikhun attack was fabricated by the United States.

The OPCW has in the past determined that civilians in Syria may have been exposed to chemicals even after the Syrian government agreed to a 2013 deal, brokered by the U.S. and Russia, to surrender its chemical weapons.