At least three children and 18 others have been killed in a series of air strikes on the opposition-controlled town of Kafranbel in north-western Syria, according to activists.
The activist-run Kafranbel Media Centre published a list of 22 dead from the Russian or Syrian government airstrikes.
The Britain-based Syrian Observatory for Human Rights monitoring group was able to confirm 21 dead, among them members of the local police force. It said the airstrikes hit the town's main marketplace.
Russia's military announced last month it was resuming its airstrikes on the north-western Idlib province and central Homs province in support of the government's efforts to suppress a years-long uprising against its national authority. Kafranbel is not on any front lines of the raging war.
Earlier Syria's army offered rebel fighters in besieged eastern Aleppo an opportunity to leave the city with their lives.
Army spokesman Brigadier Gen Samir Suleiman said those who choose to stay will face "inevitable death".
Government forces and allied militias are attempting to collapse an opposition pocket on the city's eastern side.
"We will continue fighting until we restore stability and security to all neighbourhoods" of Aleppo, the brigadier said.
He said the Syrian army had retaken more than 50% of the districts in eastern Aleppo.