Ethiopia's Prime Minister Meles Zenawi has acknowledged that his troops cannot withdraw from the conflict in Somalia.
The Ethiopians are not popular in Somalia
Mr Meles said he had expected to withdraw his soldiers earlier in the year, after Islamists had been driven out of the Somali capital, Mogadishu.
But he said divisions within the Somali government had left it unable to replace the Ethiopians, while not enough peacekeepers had arrived.
Some 60% of Mogadishu residents have fled clashes in the city, the UN says.
The Ethiopians intervened a year ago to oust the Union of Islamic Courts, which had taken control of much of southern Somalia.
Their presence is unpopular in Mogadishu and earlier this month, insurgents dragged the bodies of Ethiopian troops through the city.
"Having done the main work, we had the belief and expectations that a situation would be created for us to be able to withdraw," Mr Meles told MPs.
"However, this belief and expectations could not be met according to our plan."
He has always said the Ethiopians would pull out when a peacekeeping force was deployed.
But only 1,600 Ugandans have arrived, from a planned 8,000-strong African Union force.
The UN is divided on plans for it take over the mission.
UN chief Ban Ki-moon says it is too dangerous to send troops to Mogadishu.
The UN refugee agency says one million people have fled their homes in Somalia, including 200,000 this month, following the latest clashes between insurgents and the Ethiopian-backed government.
Last week, new Somali Prime Minister Nur Adde said he wanted to hold talks with the opposition.
Somalia has not had a functioning national government since President Mohamed Siad Barre was overthrown in 1991.