MOGADISHU, Somalia — Islamic extremist militants killed at least 20 Somali soldiers in an ambush, a military officer who survived the attack said, as the government acknowledged damage to military vehicles but disclosed no troop casualties.

The al-Qaida-linked al-Shabab group, which has fought Somalia’s government for nearly two decades, claimed responsibility for Monday’s attack near Jameeca village in southern Somalia.

The Defense Ministry said its troops killed about 75 militants and wounded 56 during hours of fighting. Al-Shabab claimed it killed 321 soldiers and captured prisoners and military equipment.

The casualty figures and claims of captured soldiers and equipment could not be independently verified.

Abshir Abdikarim, a military officer traveling with the convoy, told The Associated Press by phone late Tuesday that he saw at least 20 of his fellow soldiers dead after the attack. He said troops had advanced from Leego into Jameeca, in Burhakaba district in the Bay region, where they exchanged heavy gunfire with militants.

Some soldiers previously reported missing reached Baledogle on Tuesday, he said, while others remained unaccounted for.

The ministry described the confrontation as an assault on militant positions. Al-Shabab said its fighters ambushed a convoy advancing into territory under its control.

The ministry said militants used explosives-laden vehicles to attack army vehicles, damaging some of them. It did not specify how many were damaged or address the claims that soldiers had been captured.

Al-Shabab said it seized Turkish-supplied armored vehicles, armed pickup trucks, supply trucks, weapons and ammunition.

African Union troops pushed al-Shabab out of Mogadishu in 2011, but the group adapted through guerrilla warfare, suicide bombings and targeted assassinations.

Somali authorities have reported territorial gains during a U.S.-backed military campaign, although access restrictions have made those claims difficult to verify independently. The militants have retained the ability to operate across large areas of central and southern Somalia.

The fighting comes amid a separate struggle for control of South West state. Government troops last month clashed near Baidoa with militias loyal to former regional President Abdiaziz Hassan Mohamed Laftagareen, who resigned after federal forces seized the city in March.

The Defense Ministry said government forces would continue to target al-Shabab positions and disrupt efforts by its fighters to regroup.