A Shabaab military leader in Somalia is "presumed killed" following recent US air strikes, Pentagon officials said Wednesday.

The airstrike carried out on May 27 targeted top Shabaab military commander Abdullahi Haji Da'ud, Pentagon spokesman Peter Cook told reporters.

Another US official told reporters in Washington that the senior Shabaab militant is believed to have been killed in the attack.

"Da'ud was one of Shabaab's most senior military planners and served as a principal coordinator of (the group's) militia attacks in Somalia, Kenya, and Uganda," Cook told reporters in San Diego.

The Shabaab -- a group fighting to overthrow the internationally backed government in Mogadishu -- has also vowed retribution against "Western crusaders" who it says are guilty of offenses against Muslims in Somalia.

The capital city has a contingent of some 22,000 troops from the African Union to help bolster the government in its battle against Shabaab insurgents.