Aden Adde International Airport hosts peacekeepers, the offices of UN organisations and diplomatic missions.

A police spokesman told the BBC that five of the dead were foreigners, including an African Union force soldier.

The nationalities of those killed have not yet been established.

Two of the attackers - suspected jihadists - were also killed as they reportedly tried to force their way into the secure zone.

Witnesses have told the BBC they heard heavy gunfire and saw black smoke billowing from a section of the airport. Other reports say the UN was hit by mortars.

The al-Qaeda-linked al-Shabab group said it was behind the attack.

Its fighters have stepped up attacks as much-delayed parliamentary elections proceed using a complex and indirect system.