U.S. warplanes on Saturday killed an estimated 150 militants during a series of airstrikes at a terrorist training camp in Somalia, the Pentagon announced Monday.
The strikes were carried out by manned and unmanned aircraft at a training facility for the militant group al-Shabaab about 120 miles north of the Somali capital, Mogadishu, officials said.
The Islamist group was behind the 2013 Nairobi shopping mall attack which killed more than 60 people, as well as last year's attack on Garissa University in northeastern Kenya, in which 148 people were killed. A number of other deadly attacks on the Kenyan-Somali border have prompted the African Union to send fighters to combat the group.
Pentagon Press Secretary Peter Cook said the fighters at the camp "posed an imminent threat" to the U.S. and African Union fighters.
"The removal of these fighters degrades al-Shabaab's ability to meet the group's objectives in Somalia, including recruiting new members, establishing bases, and planning attacks on U.S. and [African Union] forces," Cook said.
According to the New York Times, the bombing occurred during a "graduation ceremony" at the training camp for the al Qaeda affiliate.
"They were standing outdoors in formation," one unnamed official told the newspaper.
According to CNN, the camp, which had been under observation for several weeks, had some 200 fighters on site.
It's not the first time the U.S. has used airstrikes to combat al-Shabaab. In March 2014, the Pentagon said it had killed Adan Garar, a member of the group's intelligence and security wing, in an airstrike in Somalia's south.
The senior militant was one of the group's key operatives and was said to be behind the 2013 Westgate Mall attack.