A United Nations report blames Syrian government forces for an April sarin gas attack on a rebel-held village that killed at least 87 people.
"The panel is confident that the Syrian Arab Republic is responsible for the release of sarin at Khan Sheikhun on 4 April 2017," states the report released on October 26.
The finding was part of the Joint Investigative Mechanism's (JIM) long-awaited report on the incident in the Syrian village of Khan Sheikhun. At least 30 children were among the dead in the attack.
An earlier investigation by the Organization for the Prohibition of Chemical Weapons (OPCW) had found evidence that the attack had been carried out by Syrian forces using the banned nerve gas.
The United States at the time blamed President Bashar al-Assad's government and launched a punitive strike on Shayrat air base, from where the OPCW report said the plane took off.
Moscow and Damascus have denied that Syria was behind the attack, claiming instead that rebel forces were responsible and had set off the sarin attack with an explosion from within the village.
Russian Ambassador Mikhail Ulyanov has accused the JIM team of failing to sample for sarin at the Shayrat airfield, a move he said was "scandalous" and likely would result in a "biased" report on the incident.
On October 24, Russia vetoed a Security Council resolution that would have extended for one year the mandate of the JIM, which is a joint effort by the UN and the OPCW to investigate chemical-weapons attacks in Syria.