Somali Islamists al Shabaab said they had ambushed a group of military trainees on Monday southwest of the capital Mogadishu and killed 30 of them, though the claim could not be independently confirmed.

A Somali military officer confirmed the ambush but said fighting was still going on and that no death toll was immediately available.

The ambush came a day after at least 13 people were killed after al Shabaab militants stormed a hotel in Mogadishu where government officials and lawmakers stay.

The militants, which aim to topple the Western-backed Somali government, and local authorities often cite different numbers of casualties after such attacks.

The government is battling to rebuild the Horn of Africa nation after more than two decades of conflict. Al Shabaab ruled large parts of Somalia until 2011, when it was driven out of Mogadishu by African and Somali troops.

"We understand al Shabaab ambushed the Somali military commando trainees and captured two military pickup trucks," Ahmed Ibrahim, the military officer, told Reuters.

"It is too early to know what the casualties are because fighting is still going on in the jungle," he said.

Al Shabaab's military spokesman, Sheikh Abdiasis Abu Musab, said his group had killed 30 commando trainees and seized four military trucks.

"We are pursuing the rest who fled," he said.

(Writing by Edith Honan; Editing by Gareth Jones)