Ethiopian troops will start withdrawing from Somalia "within the next few days", said Prime Minister Meles Zenawi.
He could not guarantee that Ethiopian troops would stay in Somalia until the proposed African peace corps was ready.
"We want to withdraw as soon as possible, but we will do it in a responsible way," Meles told BBC on Friday.
In the Ethiopian capital, the African Union's security council debated the planned 8,000 strong Somalia mission. So far only Uganda has confirmed it would send 1,500 troops.
In the meantime, three militia heads handed over 60 so-called "technicals" - platform trucks with mounted missiles - to the interim government in Mogadishu. Their warriors were to be included in a national army.
Another four warlords promised to disarm their militias but have not handed over any weapons so far.
The UN envoy for Somalia, Francois Fall, visited the capital on Thursday - the first time since Islamic militias had been ejected from Mogadishu.
He appealed to the interim government to use the "best chance of peace for 16 years".
The Ethiopian government had sent troops into the neighbouring country at the end of December to defend the weak interim government against the Islamic militias.
The US also intervened in the conflict and tried in vain to hit Al Qaeda terrorists in an air raid.