MOGADISHU, March 20 (Xinhua) -- At least six al-Shabab fighters were killed and several others injured in heavy fighting with the Somali National Army in southern Somalia, officials said Tuesday.

Somali Army official Abdirahman Ibrahim Muhamed said the militants ambushed an army base in Budhubo town, in Gedo region, on Monday evening, sparking fighting that lasted several hours.

"Somalia National Army killed six terrorists in Burdhubo town and wounded more of them during the fighting," Muhamed said. "We are safe and there are no casualties on our side."

About 90 militant fighters took part in the attack, he said.

Al-Shabab said on its affiliated websites that its fighters staged major attacks against SNA and Ethiopian bases in Burdhubo town overnight with casualties.

Independent sources said at least two civilians were killed during the fighting between the two sides.

Budhubo was calm after soldiers from the African Union Mission in Somalia (AMISOM) regained control.

The al-Qaida-linked militant group has lost control of several small towns in the Horn of Africa nation, including in the restive city of Mogadishu, but still manages to stage assaults on military bases and government facilities, including AU bases.