A powerful commander in western Somalia has stepped down from his governmental post, saying Ethiopia has renewed military involvement in his country.

Sheikh Abdirahman Ibrahim Ma'ow, the de facto governor of Hiraan province and an influential member of the ruling Union of Islamic Courts (UIC), announced on Monday that he would no longer back the transitional federal government (TFG).

"As of today, we clearly state that we are withdrawing our backing and can no longer be considered pro-government," Sheikh Ma'ow told reporters at a press conference in the town of Beledweyn, the provincial capital of the Hiran region.

The top commander called the TFG "weak", adding that it was incapable of implementing "Shari'ah law" across the war-torn Horn of Africa country.

Sheikh Ma'ow made no secret of his irritation over the deployment of Ethiopian troop in Somalia.

"I am not happy with the intervention of foreign forces, particularly Ethiopian forces in Somalia," he said.

Hundreds of Ethiopian forces poured into Beledweyn over the weekend, with more than 20 military trucks, driving west towards the Somalia-Ethiopia international border, Radio Garowe reported.

The deployment follows a joint military effort by pro-government forces and Ethiopian troops to retake southwestern Somalia form al-Shabaab militants.

According to Somali officials, the Ethiopian soldiers have now retreated from bases around Beletwein. However, unconfirmed reports say some Ethiopian army units have not yet withdrawn.

Addis Ababa has repeatedly rerjected the presence of its forces on Somali soil.