More than 150 people have reportedly been killed in a US drone attack in Somalia over the weekend.

Pentagon spokesman Captain Jeff Davis claimed on Monday that the fatalities occurred on Saturday when the drone carried out the strike on a training camp of al-Shabab militants about 120 miles (195 kilometers) north of the Somali capital of Mogadishu.

The militants “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," said Davis.

Declining to give further details, Davis noted that the training camp had been under surveillance for some time prior to the drone attack.

Somalia is the sixth country, where the United States has used assassination drones to launch missile strikes. The US military has also used drones in Afghanistan, Pakistan, Libya, Iraq, and Yemen.

Somalia has been the scene of deadly clashes between government forces and al-Shabab militants since 2006.

The militants have been pushed out of Mogadishu and other major cities by government troops and the African Union Mission to Somalia, which is largely made up of troops from Ethiopia, Uganda, Burundi, Djibouti, Sierra Leone, and Kenya.