Displaced Somalis trickled back to their bullet-scarred homes in Mogadishu on Wednesday, despite attacks by Islamist insurgents on police stations in the capital that killed about 20 people.

Rebel factions opposed to the government and African Union (AU) peacekeepers are seeking to exploit a power vacuum after thousands of Ethiopian soldiers supporting the U.N.-backed interim administration quit the city last week.

But the withdrawal of the mostly Christian troops, seen as occupiers by many Somalis, prompted some families uprooted by two years of conflict to venture home.

Hasna Abukar said she hoped her six children would now recover from the diarrhoea they suffered in a squalid camp for tens of thousands of civilians who fled to the city's outskirts.

"I am very glad to return," said Abukar, whose husband was killed by an artillery shell a year ago.

Others were not so happy. In one nearby street, Abdi Hussein Kassim surveyed the wreckage of his bomb-damaged home.

"This house was near an Ethiopian base that the Islamists often attacked. Now it is nothing but rubble," he told Reuters.

Some analysts hope the Ethiopian withdrawal will spur opposition Islamists to join a more inclusive administration for the volatile Horn of Africa nation, which Washington fears could become a safe haven for militants linked to al Qaeda.

A new president is due to be elected at U.N.-led talks in Djibouti by Jan. 26 after former president Abdullahi Yusuf resigned. On Wednesday, Yemen said it had agreed to host Yusuf and his family after he asked to live there. [nLL40404]

The U.N. envoy to Somalia, Ahmedou Ould-Abdallah, was due in Djibouti on Wednesday to push forward talks on forming a new administration between the government and the two wings of the opposition Alliance for the Re-Liberation of Somalia.

But many Somalis fear more bloodshed, especially from hardline al Shabaab Islamists who have vowed to attack the departing Ethiopians, AU peace mission and government targets -- in a bid to impose their brand of sharia law.

Abdifatah Ibrahim Shaweye, deputy governor of Mogadishu, said 19 people were killed, including four insurgents, when rebels hit three police stations in the capital late on Tuesday.

"We killed four and captured two of their colleagues alive," Shaweye told Reuters. "The Ethiopians have pulled out and we shall deal with these chaotic Islamists who are against peace."

Fighting has killed more than 16,000 Somali civilians since the start of 2007 and driven a million others from their homes. Combined with drought, that displacement has triggered a humanitarian crisis that aid workers say is Africa's most acute.

"I can't consider taking my grandchildren back to Mogadishu yet because we are still hearing threats from the Islamists that they will attack AU peacekeepers," local woman Awralla Abdulle said by telephone from a camp at Elasha, south of the city.