Reuters/Mogadishu

Al Shabaab militants attacked an African Union (AU) base in southern Somalia early on Tuesday, the militant group and residents said, and said they had killed dozens of soldiers.

The al Qaeda-aligned militants said one of their fighters rammed a car bomb into the base and then gunmen poured inside the facility run by the AU peacekeeping mission in Somalia, AMISOM.

Al Shabaab said 50 peacekeepers were killed in the attack on Janale base, about 90 km (55 miles) south of the capital, Mogadishu. In the past, the group has exaggerated the number of troops it has killed and officials have played down losses.

"Now Janale base of AMISOM is under our control," Sheikh Abdiasis Abu Musab, Al Shabaab's military operations spokesman, told Reuters.

AMISOM disputed al Shabaab's claims that the militants had routed its peacekeepers.

"AMISOM can confirm that the base is still under AMISOM control. Reports that the base has been taken over and our weapons captured are false," the AU peacekeeping force said on its Twitter feed, without giving details on casaulties.

Captain Bilow Idow, a Somali military officer based in a town near Janale, said the base was effectively cut off as the militants had destroyed a nearby bridge.

"No reinforcement can reach there," Idow said. "There is much death and damage."

Government officials could not be reached for comment.

"After morning prayers we heard a big explosion followed by heavy gunfire in the AMISOM base. We do not have further details as we are indoors," Janale resident Ahmed Olow told Reuters.

Al Shabaab, which wants to topple a Western-backed government and impose its own strict interpretation of Islam on Somalia, has also carried out attacks against neighbouring countries such as Kenya and Uganda to retaliate for troops being sent to Somalia as part of the AU peacekeeping force.