A week-old ceasefire agreement in northwest Syria appeared to hold on Sunday after it was violated for the first time overnight, a monitoring group said.
An online statement attributed to insurgent alliance the Army of Conquest said rebels shelled Shi'ite village al-Foua in retaliation for government attacks on nearby areas and in the city of Homs further south.
The insurgents said government forces had violated the ceasefire.
Under the Iranian- and Turkish-backed ceasefire, warring sides agreed to cease hostilities in at least two villages in northwestern province Idlib, and a town near the Lebanese border, for up to six months.
During that time, insurgent fighters are to withdraw from the border town, Zabadani, where they are surrounded by pro-government forces. In return, civilians would be evacuated from the Shi'ite villages of al-Foua and Kefraya in Idlib which are under rebel siege.
Rebels shelled al-Foua overnight, the Syrian Observatory for Human Rights said.
Shortly before, government forces had dropped barrel bombs on nearby village Taftanaz. The Observatory has said Taftanaz is also included in the ceasefire.
The Homs attack, a rocket fired at a rebel-controlled neighborhood, killed at least 17 people including four children on Saturday, the Observatory said.
