America's deadliest drone strike

The United States has carried out the deadliest recorded strike in the history of its drone campaign. Photo / File

The United States has carried out the deadliest recorded strike in the history of its drone campaign, killing about 150 al-Shabaab fighters during a single raid in Somalia.

The target was a training camp at Raso in the Hiran region of central Somalia, about 200km north of the capital, Mogadishu.

Until this attack, American Predator and Reaper drones had carried out between 18 and 22 raids in Somalia since 2007, killing a maximum of 126 people, according to the Bureau of Investigative Journalism.

The latest strike claimed more lives than all of the previous attacks in Somalia put together.

Al-Shabaab once formed part of al-Qaeda but has now split over whether to declare allegiance to Isis (Islamic State). Until 2012, this radical Islamist movement controlled most of southern and central Somalia, including large areas of Mogadishu itself.

Since then, African solders fighting with Western training, logistics and intelligence support have forced al-Shabaab out of Mogadishu and most urban centres in Somalia. But the group still mounts regular attacks across a wide expanse of territory, including over the border in Kenya.

Al-Shabaab claimed responsibility for the massacre in Westgate shopping mall in Nairobi, which claimed 63 lives in 2013, and a similar assault on Garissa University in north-eastern Kenya, which killed 148 last year.

US drones are based at Camp Lemonier in neighbouring Djibouti, from where they have been dispatched to kill individual al-Shabaab commanders. But the latest attack, which took place last week but was only made public yesterday, was on a completely different scale. The drone appears to have caught a large number of fighters in one location, inflicting a higher death toll than any single strike, whether in Pakistan, Yemen or anywhere else.

Captain Jeff Davis, a Pentagon spokesman, confirmed a "successful strike" on al-Shabaab fighters who were allegedly "training for a large-scale attack".

The Raso camp had been under surveillance for some time before the drone fired its missiles. The evidence led US analysts to conclude that the targets were about to leave the camp to carry out their mission. Davis said the people who were killed "posed an imminent threat to US and African Union forces".