BENGHAZI, Libya — A Libyan official says militants suspected of links to the extremist Islamic State group have killed at least four people, including security forces, at a checkpoint in western Libya.

Miftah Hamadi, mayor of the town of Zliten, said the attack that took place Thursday outside of town left four others wounded, at least two of them critical. It wasn't immediately clear if the casualties included civilians.

Hamadi said one of the militants who fled the scene after the attack was later killed.

Islamic extremists expanded their reach in Libya after the 2011 uprising plunged the country into chaos and toppled and later killed longtime dictator Moammar Gadhafi.

IS was driven from its main stronghold in the country, the coastal city of Sirte, in 2016 and fled into the Libyan interior.