At least 34 civilians, including 11 children, were killed on Monday in a series of air strikes on villages held by the Islamic State group in central Syria, a monitor said.
The Syrian Observatory for Human Rights said a barrage of air raids hit Oqayrabat and other nearby villages in the central province of Hama at dawn.
“There are dozens of people wounded, and the toll may rise because some of them are in critical condition and because of the lack of medical capacities,” the Britain-based Observatory said.
Observatory head Rami Abdel Rahman said he could not confirm if the strikes on the east of Hama province were carried out by Syrian or Russian warplanes.
He noted cases of suffocation but could not confirm accusations of a chemical attack.
A panel set up by the UN, known as the Joint Investigative Mechanism, has determined during a year-long probe that Syrian government forces carried out three chlorine gas attacks on villages in 2014 and 2015.
The panel consisting of UN and experts from the Organisation for the Prohibition of Chemical Weapons (OPCW) also found that the IS group -- which captured a large swathe of Iraq and Syria in 2014 -- was behind a mustard gas attack in Syria in August 2015.
Oqayrabat lies northwest of Palmyra, the ancient desert city that was recaptured by IS at the weekend.
Syrian government forces, backed by their Russian ally, had driven IS from Palmyra in May.