WASHINGTON -- A militant leader who helped plan the 2013 attack at a shopping mall in Kenya was killed last week in a drone strike, the Pentagon said Wednesday.

Adan Garar, who the U.S. Defense Department had identified as a member of the intelligence and security wing of the Somalia-based al-Shabaab group, was killed by an armed drone on March 12. The strike targeted a vehicle in which Garar was riding, the Defense Department said.

“The attack was a success and resulted in the death of Garar,” the statement said. The strike occurred in the vicinity of Diinsoor, Somalia.

The Pentagon first announced the strike last week as an operation against “a high-value target,” but would not publicly confirm then that Mr. Garar was killed in the strike.

The Pentagon called the confirmation of Garar’s death a significant blow to al-Shabaab, which is mainly centered in Somalia. Mr. Garar was involved in planning operations to target U.S. and Western interests, as well as attacks in the region, officials said.