SANAA, (Reuters) – Two al Qaeda-linked militants and a pro-government tribesman were killed in clashes in Yemen’s restive south on Sunday, a local official and a tribesman said.

Al Qaeda in the Arabian Peninsula has made its base in the impoverished state, which slid into chaos last year after protests that eventually forced veteran ruler Ali Abdullah Saleh to step down.

The group has mounted operations in neighboring Saudi Arabia as well as attempting to launch attacks against the United States.

The Yemeni army helped by local tribes launched a U.S.-backed drive in May to drive Islamist militants from Ansar al-Sharia (Partisans of Islamic Law), an offshoot of al Qaeda, out of several southern towns they had held for more than a year.

The two militants killed in Sunday’s violence in Abyan province were from Somalia and Pakistan, the tribesman said.

Ansar al-Sharia has attracted hundreds of foreign fighters since it seized the towns in the south and declared them Islamic emirates. Some of those militants had previously fought in Afghanistan.

A defense ministry website said an al Qaeda commander, Khaled Batees, was among eight Islamist militants killed by a U.S. drone strike in a remote part of the eastern province of Hadramout on Friday.

Batees had previously been captured by security forces but escaped prison during the uprising last year.

Washington, which fears the spread of Islamist militancy in Yemen, has stepped up attacks by unmanned aircraft this year.