TUNIS (Reuters) - Tunisian armed forces killed two Islamist militants including a senior commander in a mountain raid near the western border with Algeria late on Tuesday, security sources said.

“Two terrorists were killed and weapons were seized during an ambush that National Guard units set up against a terrorist group,” in Kasserine region, National Guard spokesman Colonel Major Khelifa Chibani told state news agency TAP.

Tunisian radio station Mosaique FM identified the commander as Mourad Chaieb, the Algerian leader of Okba Bin Nafaa, a group that has skirmished for years with security forces in Tunisia’s mountainous interior.

Its members are mainly aligned with al Qaeda’s north African branch, al Qaeda in the Islamic Maghreb, which has a presence over the border in eastern Algeria. Some fighters have switched their loyalty to Islamic State.

Chaieb is a brother of the former leader of the group, Khaled Chaieb, who was killed by security forces two years ago.

Tunisia has been on high alert since 2015, when Islamic State gunmen killed dozens of foreign tourists in two attacks at a museum in the capital, Tunis, and on a beach in the resort city of Sousse.

The country also faces a potential threat from Tunisian militants returning from abroad. More than 3,000 are thought to have left to fight for jihadist groups in Syria, Iraq and Libya over the past four years.