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 al-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 Jableh, near Latakia, killed at least 16. It added that security forces killed 28