Nairobi/Mogadishu - The man named prime minister by Somali President Abdullahi Yusuf Ahmed in a controversial move last week resigned on Wednesday, saying his appointment was an impediment to peace.

Mohamed Mahamud Guled, who was appointed to replace Nur Hassan Hussein in a move condemned as unconstitutional, said he was destabilizing the government and did not want to get in the way of an ongoing peace process.

Yusuf fired Hussein and his cabinet on December 14, saying Hussein was "unable to perform his duties."

However, parliament voted overwhelmingly to back Hussein and regional governments imposed sanctions on Yusuf in response to the sacking.

Yusuf has been at loggerheads with his prime minister since the summer, when Hussein fired the Mogadishu mayor, a close ally of Yusuf.

Islamist insurgents have taken advantage of the political infighting to advance to the edge of Mogadishu.

Somalia has been embroiled in chaos ever since the 1991 ouster of dictator Mohamed Siad Barre.

The crisis has deepened since Ethiopian forces helped kick out a hardline Islamist regime in the last half of 2006, sparking a bloody insurgency that has killed over 10,000 civilians.

Hussein, who came to power last November, has accused Yusuf of trying to derail the UN-sponsored peace process between the Transitional Federal Government and opposition group the Alliance of the Re-Liberation of Somalia (ARS).

He says is going to continue as prime minister.

The political chaos comes as Ethiopia prepares to pull its troops out of Somalia.

Al-Shabaab has refused to take part in the peace process and there are fears that it will overrun Somalia completely should the Ethiopians and AU leave.

The insurgent group has been implementing strict Islamic law as it takes over towns, and many are concerned of a radicalization of the population should it gain complete control.

The US says that al-Shabaab has close links to al-Qaeda, and one the alleged masterminds of the 1998 bombings of the US embassies in Kenya and Tanzania is believed to now be based in Somalia. (dpa)