A defense official says the coordination cell became fully operational in Mogadishu in mid-December and is staffed by “less than five” military personnel. The team members first began arriving in October to establish their office and living arrangements at the airport in the Somali capital of Mogadishu.

Their presence resulted from a request in September made to Defense Secretary Chuck Hagel in September by the Somali government and AMISOM.

Somalia has had a central government since August 2012, but al-Shabab still controls large parts of the country. The African Union forces control most of Mogadishu, while troops from Ethiopia and Kenya control regions near their borders.

Washington has spent more than 500 million dollars to train and equip the African Union forces since 2007, and poured in additional 170 million dollars to help build up the nascent Somali national army, the Post said.

It said drones from a U.S. base in neighboring Djibouti have conducted surveillance missions and occasional airstrikes from Somalia's skies, with U.S. Special Operations forces also setting foot on Somali territory "on rare occasions" to carry out brief counterterrorism raids and hostage rescues.

The Central Intelligence Agency has also quietly operated a base in Somalia for years and finances Somali security forces, the Post said.