Ethiopia announced Friday its troops will withdraw from Somalia by the end of 2008, ending an ill-fated two-year occupation but raising fears of a security vacuum in the war-ravaged country.
With unprepared African Union troops confined to some parts of Mogadishu and joint units not yet operational, a hasty pull-out would leave most of Somalia under the control of the Islamist group Shebab and its allies.
Ethiopian foreign ministry spokesman Wahide Belay said that the deadline for the pullout was announced in a letter sent on Tuesday to UN Secretary-General Ban Ki-moon and African Union Commission Chairman Jean Ping.
"Foreign Minister Seyoum Mesfin has stated that Ethiopia had decided to withdraw at the end of the year," Wahide said.
Both Ping and Ban's Somalia envoy expressed concern at the move in remarks Friday.
Ethiopia sent troops to Somalia in 2006 to oust the Islamic Courts Union (ICU), a radical group which had conquered most of the country and was imposing a strict form of Sharia law.
Ethiopian troops -- now estimted at around 3,000 -- were meant to prop up the embattled transitional federal government but the internationally-backed authorities never succeeded in asserting their power on the restive country.
The Shebab, the former youth and military wing of the ICU, has since waged a bruising guerrilla war against Somali government troops and Ethiopian forces.
A recent agreement between the more moderate members of the Somali opposition and the transitional government was reached in Djibouti for a gradual withdrawal of Ethiopian troops, but no deadline had been announced.
"We have concluded that it's inappropriate for Ethiopia to maintain its troops in Somalia," Wahide told AFP.
"We have done our job and we are proud of it, but the expectations that we had from the international community were never fulfilled. But that said, we will withdraw in a responsible manner," he said.
In 2007, the African Union started deploying peacekeepers in Mogadishu in a mission dubbed AMISOM but their troops have failed to curb the daily fighting, which has killed thousands of civilians this year alone.
The UN-sponsored agreement signed in Djibouti provides for AMISOM to take over security responsibilities while joint units involving the government and the opposition prepare to become operational.
But speaking to reporters on Thursday, Jean Ping said that a hasty Ethiopian withdrawal from Somalia would have dire consequences.
"It's a possible scenario and a disaster scenario," he said, explaining that the 3,600 African peacekeepers have threatened to pull out as well if a smooth transition was not guaranteed.
"If the transitional government continues to quarrel, if those we came here to help can't agree and the Ethiopians pull out lock, stock and barrel... and African troops too decide to leave, then we have the worst possible scenario."
The United Nations' top envoy for Somalia, Ahmedou Ould Abdallah, told AFP that the international community should hold urgent talks with Ethiopia.
"What concerns all of us is achieving stability in Somalia. The permanent members of the UN Security Council, the European Union and African Union therefore need to urgently discuss this withdrawal with Ethiopia," he said.
"I have invited the international community to talk seriously with the Ethiopians, to understand their position and give them the necessary support to avoid a security vacuum."
Somalia's president, Abdullahi Yusuf Ahmed, and prime minister, Nur Hassan Hussein, have been in open disagreement in recent weeks.
AU peacekeepers have already started taking over some positions from the Ethiopian army in the capital Mogadishu, with the Shebab closing in on the capital after conquering most of the country.
Somalia's insurgent Islamist leader Sheikh Hassan Dahir Aweys was sceptical, stressing that Addis Ababa had promised its troops would be out within weeks when they invaded.
He also validated AU fears, suggesting that insurgents would combat the AU once the Ethiopians had left.
"There is no difference between Ethiopian troops and AMISOM, they both kill women and children, displace hundreds of thousands of people," Sheikh Aweys told AFP.
The Islamist camp's hardliners had consistently refused to join the Djibouti peace talks so long as Ethiopian troops remained on Somali soil.
Ethiopia has repeatedly said in recent months that it did not intend to stay in Somalia indefinitely but also warned it would rush back in the minute an Islamist group takes power.