Turkey has backed anti-Assad Syrian forces for years and maintains bases in Syria's north. Its defence ministry said there was no surge in deployments late last week, after sources in Syria said more armored vehicles had crossed the border.

A Syrian security source said the pace of fighting had slowed around Latakia, Jabla and Baniyas, while forces searched surrounding mountainous areas where an estimated 5,000 pro-Assad insurgents were hiding.

A monitoring group says 973 civilians have been killed in revenge attacks against the Alawite sect since Thursday.