(Reuters) - Islamist groups including al Qaeda's Nusra Front have seized the Syrian city of Idlib for the first time since the conflict in the country began, fighters and a monitoring group said on Saturday.

By taking Idlib, the capital of a northwestern province of the same name, the insurgents now control a second province after Raqqa, a stronghold of the Islamic State group and target of U.S.-led air strikes.

Syrian officials could not be immediately reached for comment.

(Reporting by Mariam Karouny; Editing by Toby Chopra)