A military helicopter operated by the African Union crashed and caught fire Wednesday at the airport in Somalia's capital Mogadishu, killing at least three people, according to Somali authorities.

The helicopter was arriving from Balli-doogle Airfield in the Lower Shabelle region in southern Somalia with eight people on board.

The helicopter originally belonged to the Ugandan Air Force but was being operated by the African Union peacekeeping mission, said Artan Mohamed, who heads the immigration office at Mogadishu's Aden Abdulle airport.

The crash occurred at around 7:30 am. The exact number of casualties remains unclear. At least three people have been confirmed dead, according to Mohamed.

A Ugandan army spokesperson, Felix Kulaigye, said three people had escaped the helicopter with burns and that the remaining five passengers were "yet to be accounted for."

The three survivors were taken to hospital for treatment while "search and rescue operations are currently underway to retrieve the remaining crew and passengers", the AU peacekeeping mission said in a statement.

The impact of the crash also caused munitions onboard the helicopter to detonate, injuring three civilians, Kulaigye reported.

Aviation officer Omar Farah, who was among the first to reach the wreckage, told The Associated Press that he “saw the helicopter spinning and then it fell very fast.”

There was "a huge explosion and smoke everywhere”, said Abdirahim Ali, a nearby resident who also witnessed the crash.

Minor delays were reported at the airport, but flights and other operations have since resumed.

The African Union peacekeeping mission, known as the African Union Support and Stabilization Mission in Somalia (AUSSOM), is helping Somali authorities to fight the extremist rebels of al-Shabab, a group that opposes the presence of foreign troops in the Horn of Africa nation.

The mission includes troops from countries such as Uganda and Kenya.