MOGADISHU, Somalia - The spate of deadly violence in Somalia's capital in recent days is the work of an Islamic movement that was driven from Mogadishu and much of the country's south last month, a government spokesman said Saturday.

"They want to destabilize the country to show that there is no peace in Somalia," Abdirahman Dinari said.

No group has claimed responsibility for the attacks and Dinari did not offer evidence to prove the Council of Islamic Courts was behind the violence. But the radical group has vowed to launch an Iraq-style guerrilla war.

The Somali government has been putting more troops on the streets this week as Ethiopian troops -- whose military strength was crucial to helping drive out the Islamic militia -- begin pulling out of the country.

The withdrawal of Ethiopia, which says it cannot afford to stay in Somalia, raises a sense of urgency for the arrival of a proposed African peacekeeping force. The African Union has approved a plan to send about 8,000 peacekeepers for a six-month mission that would eventually be taken over by the U.N.

South Africa dashed hopes Friday that it would contribute to a peacekeeping force in Somalia, with Defense Minister Mosiuoa Lekota saying the country's forces already were overstretched. Nigeria, Malawi and Uganda have said they want to contribute troops, but no firm plans are in place.

Meanwhile, the capital and other parts of the country are being wracked by violence. Gunmen launched mortars on an Ethiopian base on the outskirts of Mogadishu late Friday, prompting a brief firefight. It was not clear if there were casualties. Earlier Friday, gunfire and mortar attacks in Mogadishu killed five people and injured at least four.

Many Somalis resented the Ethiopian presence: their countries fought a war in 1977. But without Ethiopia's tanks and fighter jets, the Somali government could barely assert control outside one town and could not enter the capital, Mogadishu, which was ruled by the Council of Islamic Courts. The U.S. accused the group of having ties to al-Qaida.

Earlier this month, Ethiopian and U.S. forces were pursuing three top al-Qaida suspects but failed to capture or kill them in an AC-130 strike in the southern part of Somalia. A main target was Fazul Abdullah Mohammed, one of three senior al-Qaida members blamed for the 1998 bombings of the U.S. embassies in Kenya and Tanzania.

The U.S. Navy also has had forces in waters off the Somali coast, where they have monitored maritime traffic, boarded suspicious ships and interrogated crews in an attempt to catch anyone escaping the Somali military operations.