MOGADISHU, April 18 (Xinhua) -- At least two senior Somali army soldiers were killed and unknown others injured in a landmine attack on Wednesday near Bal'ad town in Middle Shabelle region in southern Somalia.

The two Somali National Army (SNA) soldiers including a commander were killed when militants ambushed their vehicle, prompting a fierce gunfight between the soldiers and the insurgents.

Information Minister for Hirshabelle State in Somalia Abdiweli Muhamed Abdi told Xinhua by phone that the attack was caused by a remotely controlled device which targeted an army vehicle coming from Mahaday town to Mogadishu.

"We have the report that al-Shabab militants attacked an army vehicle from Mahaday district with senior army commanders. The two soldiers were killed in the attack and some others injured in the fierce fighting that ensued," Mohamed said.

He added that there were casualties on the militants' side but could not establish the number of those killed or injured.

The terrorist group's affiliated website said that the militants killed five government soldiers, recovered weapons and later burned the military vehicle.

The latest killings come as the Somali army backed by the African Union peacekeeping force have mounted a joint offensive against the militant group in southern region.

The army officials said the operation will continue until all regions still under al-Shabab control are liberated.

The incident took place in the same region where soldiers had earlier captured five villages in Middle Shabelle region which were hitherto under the group's control.