DAMASCUS, Syria — Gunmen ambushed a Syrian police patrol in a coastal town Thursday, leaving at least 13 security members dead and many others wounded, a monitoring group and a local official said.

The attack came as tensions in Syria’s coastal region between former President Bashar Assad’s minority Alawite sect and members of Islamic groups escalate. Assad was overthrown in early December in an offensive of insurgent groups led by the Islamist Hayat Tahrir al-Sham.

The U.K.-based Syrian Observatory for Human Rights said the ambush in the town of Jableh, near the city of Latakia, killed at least 16. It added that security forces killed 28 Assad loyalists as well as three civilians.

Rami Abdurrahman, head of the monitoring group, said the gunmen who ambushed the police force are Alawites. He added that on Thursday night, pro-Assad gunmen were in full control of the former president’s hometown of Qardaha.“These are the worst clashes since the fall of the regime,” Abdurrahman said.

— The Associated Press