The Ethiopian army has poured hundreds of additional troops into southern Somalia, a day after the Ethiopian government formally announced plans to withdraw by December.

Witnesses in border towns in Bakool region told Radio Garowe that Ethiopian soldiers driving armored and military transport vehicles arrived peacefully in parts of Bay region, where the country's parliament is based.

The troops are heading for Baidoa, the capital of Bay region, with unconfirmed reports saying the troops will take part in the withdrawal process.

Ethiopia has not spoken publicy about the arrival of fresh troops.