The United States has sent a handful of military advisers to Somalia to help bolster the African Union force there, establishing the first permanent US military presence there in two decades.

The deployment, confirmed on Saturday, marks the first stationing of US troops in the troubled country since 1993, when two Black Hawk helicopters were shot down and 18 US soldiers were killed in a disastrous operation in Mogadishu.

"The US has established a military co-ordination cell in Somalia to provide planning and advisory support to the African Union Mission in Somalia [AMISOM] and Somali security forces to increase their capabilities and promote peace and security," said US Africa Command spokesman, Colonel Tom Davis.

The team was launched in October and became fully operational in December. It is based at Mogadishu airport.

A big step forward to normalisation of relations with Somalia. US defence official

A US defence official told Al Jazeera that the team numbers "fewer than five" troops but was a "big step forward to normalisation of relations with Somalia".

"This is an example of progress for Somalia," he said. "The government is getting back on its feet, mainly with the help of AMISOM. In the past number of years we haven't had any significant presence, our embassy operates out of Nairobi but we've progressed to point where [the US] feels comfortable leaving a number of personnel in Mogadishu."

AMISOM supports Somali government forces in their battle against al-Shabab.

Although al-Shabab has suffered battlefield setbacks in Somalia, it has orchestrated a number of attacks in other East African countries, including a bloody four-day siege of a shopping centre in Nairobi in September that killed dozens.

The UN Security Council in November approved an increase of 4,400 troops to the AU force, expanding it from 17,700 to more than 22,100. The AU force includes troops from Burundi, Djibouti, Kenya, Sierra Leone and Uganda.