At least four people have been killed after a military aircraft burst into flames moments after landing at the international airport in the Somali capital Mogadishu.

The victims in Friday's accident were part of the six crew on board.

Sources said the plane belonged to the Ethiopian airforce and was carrying weapons and ammunition for AMISOM, the peacekeeping mission in Somalia run by the African Union. 

AMISOM said on Twitter the crash happened shortly before 8am.

"The [AU] force commander expresses his heartfelt condolences to the government and the people of Ethiopia following the loss of crew members," AMISOM tweeted without giving the number of those killed or injured. 

Small blasts could be heard from the stricken plane and airport workers said they believed they were caused by exploding ammunition.

"We hear explosions as it burns. It is burning like hell. It is sure it will end up in ash," one security source at the airport told the Reuters news agency.

The source said the blaze was so intense firefighting crews were unable to tackle it.

Mucahit Salih Duran, head of the Turkish Red Crescent delegation in Somalia, tweeted a photo showing black smoke rising from what appeared to be a runway.

There was no immediate word on where the aircraft was flying from.

Military aircraft regularly land at Mogadishu's airport, which also serves as the headquarters for the AU force battling al Qaeda-linked Islamist fighters called al-Shabab.

Air traffic has increased significantly at the airport as Mogadishu continues on a slow recovery from decades of warfare. Two major international carriers - Turkish Airlines and Air Uganda - operate direct flights into Mogadishu.

Source: Al Jazeera and agencies