WASHINGTON - The Obama administration has sent military advisers and trainers to conflict-plagued Somalia, the first time since 1993 when two US Black Hawk helicopters were shot down in the Somalian capital of Mogadishu, the Washington Post reported on Friday, citing three anonymous US military officials.

The newspaper said the American troops, which it said number fewer than two dozens while the CBS TV network put it at three, have been in Mogadishu since October, the 20th anniversary of the so-called "Black Hawk Down" disaster in which 18 Americans were killed while on a mission to support a United Nations humanitarian operation.

The heavy losses and images of dead Americans being dragged through the streets prompted a quick US withdrawal and for years discouraged Washington from intervening in other conflicts, the Post noted.

It said the military advisers returned to advise and coordinate operations with African troops fighting to wrest control of Somalia from the al-Shabab militia, an Islamist group that announced a merger with al-Qaida two years ago.

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 US base in neighboring Djibouti have conducted surveillance missions and occasional airstrikes from Somalia's skies, with US 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.

In October, Amanda Dory, the Pentagon's top policy official for Africa, told Congress that the military would "increase our presence in Mogadishu in tandem with the State Department."

Thomas Davis, a spokesman for the Africa Command, confirmed the deployment in a statement on January 3. He said the military cell was "now fully operational."

The United States recognized the Somali government in January 2013 and reestablished diplomatic relations with the Horn of Africa nation for the first time since its central government collapsed in 1991 when a civil war broke out.

However, Washington has not reopened an embassy in Mogadishu.

Al-Shabab has plotted attacks in other countries in East Africa, including one on a shopping center in downtown Nairobi, Kenya's capital, in September that killed at least 67 people.