MOGADISHU (Reuters) - A landmine killed one person and wounded four on Tuesday in a rare attack on a mosque in an insurgent stronghold of the Somali capital, witnesses said.

They said the mine exploded as worshippers were going to the Abu Hureyra mosque in Bakara Market, an area used as a base by rebels fighting the government and African Union (AU) troops.

"We hear about explosions at mosques in Iraq, so this is an amazing thing to happen in Somalia," witness Abdallahi said.

It was not clear who was responsible for the attack in an area dominated by members of the al Qaeda-linked al Shabaab rebel group and another insurgent militia called Hizbul Islam.

In another part of Mogadishu, a suicide bomber in a truck laden with explosives targeted a new AU base set up last week in the Shangani area north of the presidential palace, witnesses said.

Major Barigye Ba-hoku, spokesman for the AU force made up of soldiers from Uganda and Burundi, said the vehicle was blown up before it could ram into the new base.

"We have foiled the attempt, we have destroyed the would-be suicide car bomb. Two of our soldiers who destroyed the car sustained minor injuries," he told Reuters.

Al Shabaab claimed responsibility for the attack in a statement and said it had killed some troops.

Insurgents have been fighting the Western-backed government in the Horn of Africa nation since the start of 2007. The rebel groups now control much of southern and central Somalia while the government is hemmed into a few blocks of the capital.