Nairobi, Kampala - Uganda on Friday confirmed that the African Union peacekeeping force in Somalia will pull out should Ethiopia stick to its promise of withdrawing its troops before the end of the year.

"If the Ethiopians pull out ... the AU force will pull out because it will not have adequate numbers," James Mugume, permanent secretary at the Ugandan Foreign Ministry, told Deutsche Presse-Agentur dpa.

The Ethiopian government in late November said it would extract its several thousand soldiers unconditionally by the end of the year.

Ethiopian Prime Minister Meles Zenawi on Thursday broke the news that the AU force would also leave and promised to help the Ugandan and Burundian peacekeepers, numbering around 3,000, to pull out.

Ethiopian forces invaded in 2006 to help kick out the Islamic Courts' Union (ICU) - a hardline Islamist regime that was in power for six months.

A bloody insurgency in Southern and Central Somalia then kicked off in early 2007.

Aid agencies say around 10,000 civilians have died and over 1 million have fled as al-Shabaab, a militant splinter group of the ICU, has made huge gains.

The insurgent group is now perched on the edge of Mogadishu and is on the verge of over-running the squabbling and ineffective Transitional Federal Government.

Should both Ethiopia and the AU leave, the only force standing between the insurgents and victory would be a collection of pro- government armed militia and poorly trained recruits.

Mugume said that the AU force would only remain in Somalia if long- standing calls for a UN peacekeeping force to be deployed were answered.

"If the Ethiopians are replaced by other troops like UN peacekeepers, a number of about 8,000, we will stay," he said.

However, the UN has appeared reluctant to deploy and analysts say this is unlikely to change.

"I don't think there is a realistic prospect for substitute troops," Roger Middleton, Horn of Africa analyst at London-based think tank Chatham House, told dpa.

The AU force was supposed to have been much larger, but many nations have failed to meet their commitments. As a result, the AU force is undermanned and overwhelmed.

Middleton said that the AU peacekeepers would have little choice but to leave should the Ethiopians stick to their promise to go.

"If the Ugandans stayed ... they would become greater targets," he said. "Even if they stayed, I don't think they would have a stabilizing impact. Their force is tiny and can't even secure (Mogadishu) airport."

Hardline Islamists have refused to talk peace unless the Ethiopians first left Somalia, but it is not clear if they will now come to the table or continue to advance.

Al-Shabaab has already rejected a peace deal agreed between moderate opposition figures and the government.

There are fears that in the absence of the common enemy, the Ethiopians, the insurgent groups will splinter and begin fighting, creating more chaos.

However, Middleton said that the worst-case scenario would be that al-Shabaab remained united and decided to finish off the government.

"The scariest scenario is that al-Shabaab holds together ... and we see an al-Shabaab regime with the attended radicalization of the population."

The US says that al-Shabaab has links to al-Qaeda. In May it launched an airstrike that killed al-Shabaab leader Aden Hashi Ayro.

Al-Shabaab has also been implementing strict sharia, or Islamic law, in the towns it has seized from the government.

So far this year, a teenage girl has been stoned to death for adultery after being raped and people have been whipped for dancing and playing music.

The developments are also unlikely to be good news for plans to fight a surge in piracy off Somalia, which peaked with the recent seizure of a Saudi supertanker carrying crude oil worth 100 million dollars.

Delegates at a international conference on Thursday said that piracy was inextricably linked to the insecurity in Somalia and called for stronger efforts to help build a stable government.

The Horn of Africa nation has been plagued by chaos and civil war since the ouster of dictator Mohamed Siad Barre in 1991. (dpa)