ADDIS ABABA, Ethiopia - The UN Security Council has not ruled out the idea of a UN peacekeeping force for Somalia, a top envoy said Saturday after meeting with African Union officials to discuss problems in Somalia and Sudan.

UN Secretary-General Ban Ki-moon has come out against such a force, but the fierce fighting that has ravaged the Somali capital of Mogadishu in the last few days appeared to weigh on the diplomats' minds.

"The question of a United Nations peacekeeping mission remains on the table," Britain's UN Ambassador John Sawers told journalists after hours of talks.

Sawers is leading the UN Security Council on its eight-day African trip, which will take envoys to Rwanda, Congo and Liberia.

More than 100 civilians have been killed in the last week and at least 30,000 people forced to flee their homes in Mogadishu, one of the world's most dangerous cities. Diplomats said up to 400 foreign Islamic militants were behind the anti-government attacks.

Ruhakana Rugunda, Uganda's UN ambassador, said those militants could become a threat to the entire region.

"This problem of foreign fighters needs to be contained and contained now. If not, it can escalate and cause more problems in other countries," Rugunda said.

Somalia has not had an effective government for nearly two decades.

An intricate peace deal led to the election of a moderate Islamic leader as president and Ethiopia withdrawing its troops after a two-year deployment. Somali President Sheik Sharif Sheik Ahmed's government also promised to implement Shariah law, but even that has failed to persuade hard-line Islamic groups to end a two-year insurgency.

Burundi's AU ambassador Epiphanie Kabushemeye-Ntamwana said her country is hoping for an UN peacekeeping force. Burundi already has two battalions in Somalia as part of an AU force that guards key government officials and buildings.

The UN Security Council condemned the violence in Mogadishu on Friday and strongly supported Ahmed's government. It also expressed concern at reports that Horn of Africa nation Eritrea has supplied arms to opponents of Somalia's government in violation of an arms embargo.

The talks Saturday also focused on Sudan and its western region of Darfur, where UN officials estimate up to 300,000 people have died and about 2.7 million have been displaced since 2003.

The International Criminal Court in March issued a warrant against Sudanese President Omar al-Bashir, accusing him of orchestrating war crimes in Darfur. In response, Sudan expelled more than a dozen aid agencies that mostly worked in Darfur.

Al-Bashir denies the accusations, and Sudan has refused to co-operate with the court.

Noureddine Mezni, spokesman for the joint UN-African Union mission in Darfur, said envoys expressed concern Saturday about rising tensions between Chad and Sudan.

The two neighbours have traded accusations after Chadian rebels earlier this month launched attacks in eastern Chad, which borders Darfur. Chad, which accuses Sudan of supporting the rebels, is considering breaking ties with Sudan. Sudan has denied backing the Chadian rebels.

"There can be no solution to Darfur without normalization between the two countries, Chad and Sudan. They are neighbours, they have to coexist," said Mezni.

The UN-AU mission in Darfur is made up of 15,000 mostly African peacekeepers and remains ill-equipped. Mezni said it has not received 24 helicopters it had requested to try to protect civilians in the vast arid region.

"Air mobility is vital to do that job," Mezni said.