NAIROBI, Kenya >> A senior leader of Somali terrorist group al-Shabab, who was accused of planning multiple attacks that killed 148 Kenyans in a university town and three Americans on a military base, was killed in a U.S. military drone strike Sunday, according to Somali and American officials.

Maalim Ayman was killed by a U.S. Special Operations drone strike in a joint operation with the Somali national army, the officials said. He is believed to be responsible for the assault Jan. 5, 2020, on a military base in Manda Bay, Kenya, that killed two U.S. contractor pilots and a U.S. soldier. A third U.S. contractor and two other U.S. servicemembers were injured. Six U.S. aircraft were destroyed in the attack.

Somalia, a strategic nation located in the Horn of Africa, has been fending off attacks since 2006 by the extremist group al-Shabab, with the assistance of forces from the African Union and the United States. Ayman was believed to be the mastermind of a unit that launched attacks inside Kenya, Somalia’s southern neighbor.

Officially, the U.S. Africa Command, while confirming the strike in Somalia, did not identify the target, pending further analysis, the command said in a statement.

But a U.S. military official, speaking on condition of anonymity to discuss operational matters, said the strike successfully targeted Ayman. Somalia’s information minister confirmed the killing of Ayman.

Somalia’s president, Hassan Sheikh Mohamud, has vowed to defeat al-Shabab militarily and financially. Even though al-Shabab (which is linked to the al-Qaida terrorist group) has lost territory and fighters in recent years, it has proved to be resilient and continues to carry out deadly attacks in hotels, restaurants and ministries that have left hundreds dead.

Ayman also was said to have planned the attack in 2015 on Garissa University in northeastern Kenya, which resulted in the deaths of 148 people, most of them students. After storming the university at dawn, the gunmen shot point-blank at students, many of whom were asleep in their dormitories.