NAIROBI, Kenya — The African Union agreed yesterday to send troops to Somalia to help its new government set up operations, train new Somali security forces and stabilize the Horn of Africa nation, officials said.

Key details of the mission — including its duration and the number of troops — will be decided after talks with Somali leaders, Somali presidential spokesman Yusuf Mohamed Ismail said in Kenya.

"The force would help the new government to relocate back to the Somalia, train and provide logistic support to the new security forces in order to enable the government to fulfill the pressing task of demobilizing, disarming and helping combatants rejoin the civilian life through dialogue," he said.

The government, elected last year in Kenya following peace talks, is based in Nairobi because Mogadishu, the Somali capital, is considered too dangerous.

Somalia, a country of 7 million, has been split among clan-based militias since dictator Mohamed Siad Barre was ousted in 1991. Civil war has left more than 500,000 dead. Additionally, 3.5 million have been driven from their homes, 1.5 million of whom have taken refuge in neighboring countries.

The African Union's peace and security council agreed in principle to send the troops to Somalia during a meeting in the Ethiopian capital of Addis Ababa yesterday, spokesman Desmond Orjiako said.

The African Union's decision came a day after the Kenyan government demanded Somali leaders return home, warning that the new government risks becoming a government-in-exile if it fails to end fighting between militias in the country.

Somali President Abdullahi Yusuf Ahmed had asked the African Union to send a force to stabilize his country and help train a 30,000-strong army, which he said he hopes can be in place within a year.

The Somali leader also expressed hope that the African Union force would accomplish its mission in a year.

The AU, its meager resources already stretched by a peacekeeping operation in Sudan's troubled Darfur, urged the United Nations and the European Union to help finance the Somalia mission.

The U.N. has been hesitant to commit, given that its last peacekeeping mission there ended in a bloody withdrawal in 1995.

Uganda has already offered 2,000 troops for the AU mission.

The Somali government, currently based in the relative security of neighboring Kenya, is picking a new cabinet before going home to try and rebuild the anarchic nation and rein in its fractious militia groups.

Yusuf's credibility hinges on his returning home and quickly pacifying the lawless country, diplomats have said.

Militiamen rule a patchwork of fiefdoms in Somalia, backed by rifles, truck-mounted machine guns and rocket launchers.

The council said troops would be deployed after talks with Somali and Kenyan officials on the makeup of the force, to be named the African Mission in Somalia.