Washington - A US drone strike on a Shebaab training camp in Somalia over the weekend killed more than 150 fighters who were planning a "large-scale" attack, the Pentagon said on Monday.Pentagon spokesperson Captain Jeff Davis said the strike occurred sometime on Saturday (US time) on a camp called Raso, about 200km north of Mogadishu."The fighters were there training and were training for a large-scale attack. We know they were going to be departing the camp and they posed an imminent threat to US and [African Union] forces," Pentagon spokesperson Captain Jeff Davis said."Initial assessments are that more than 150 terrorist fighters were eliminated," he added.Davis said the group had neared the completion of specialist training to conduct "offensive operations", but he did not give any details about the assault the fighters were allegedly planning. "Their removal will degrade al-Shebaab's ability to meet the group's objectives in Somalia, which includes recruiting new members, establishing bases and planning attacks on US and Amison (African Union Mission to Somalia) forces there," he said.The training camp had been under surveillance for some time ahead of the drone strike. "There was a sense that the operational phase was about to happen," Davis said.Al-Qaeda aligned Shebaab jihadists have claimed responsiblity for a string of recent attacks including a twin bombing at a busy restaurant in the Somali city of Baidoa last month.