The Pentagon is confirming that a U.S. airstrike last week killed Adan Garar, a senior member of the al-Shabab extremist group who allegedly helped plan the 2013 Westgate Mall attack in Nairobi, Kenya, that killed 67 people.

It was widely reported shortly after the March 12 airstrike that Garar had been killed, but the Pentagon had not publicly confirmed it until Wednesday. It said in a brief statement that Garar was killed when a U.S. drone aircraft struck a vehicle in which he was riding in Somalia.

The Pentagon statement called Garar a "major threat" and said his death dealt a significant blow to al-Shabab.