By Phil Stewart

LONDON, Sept 7 (Reuters) - The U.S. military conducted two strikes in southern Somalia early this week that killed four al Qaeda-linked al Shabaab militants involved in attacks on Somali government troops, a U.S. military spokeswoman said on Wednesday.

The U.S. military has in the past used drones to target al Shabaab's senior leaders. The Pentagon said in June it carried out a strike in late May against Abdullahi Haji Da'ud, one of al Shabaab's senior military planners and served as a principal coordinator of attacks in Somalia, Kenya, and Uganda.

The latest strikes took place in Torotorow in Lower Shabelle region, on Monday.

"During a Somali-led counter-terrorism operation, a large group of armed al Shabaab fighters attacked the force, threatening the safety and security of the forces in the area," Captain Jennifer Dyrcz, a U.S. Africa Command spokeswoman, said. "In response, the U.S. conducted two self-defence strikes... killing four al Shabaab militants."

Al Shabaab was pushed out of Mogadishu by African Union peacekeeping forces in 2011 but has remained a potent antagonist in Somalia, launching frequent attacks aimed at overthrowing the Western-backed government. (Additional reporting by Feisal Omar in Mogadishu; Writing by George Obulutsa; editing by Ralph Boulton)