A rebel group that deposed Somalia's president announced a successor Tuesday, but new fighting was reported in that nation's capital. The insurgents claimed the president had fled to Kenya and asked for asylum.

Sources speaking on condition of anonymity said the situation in Mogadishu had again become "very unstable."It was not known who was shooting, but sources said it was apparently not the celebratory gunfire heard periodically since the rebels announced they had taken command Saturday night.

The rebels said that ousted President Mohamed Siad Barre fled from Somalia by boat and arrived Tuesday morning in Mombasa, a coastal town in this neighboring East African nation.

Abdullah Hussein, a rebel official in Rome, said Siad Barre had requested temporary asylum in Kenya before going to a third country. Kenya has offered Siad Barre safe passage, but the report could not be confirmed.

Earlier, a local pilot, who insisted on anonymity, had said military authorities in the southern town of Kismayu told him Siad Barre and about 100 others headed by road Monday toward Kenya, this neighboring East African country.

The rebel United Somali Congress announced the appointment of Ali Mahdi Muhammad as Somalia's new president.

The news broadcast over Radio Mogadishu said the rebels made the appointment "after considering the first decree that the U.S.C. has taken over the administration of the country and the need for a quick appointment of a head of state who can display unity pending consultations."

The reference to "pending consultations" was the only suggestion that Muhammad's administration would be an interim one, as the rebels had promised. They have said a later permanent government will be drawn from the nation's main insurgencies.

Muhammad is a businessman of the large Hawiye clan, from which the rebels draw their strength. Muhammad is in his 50s, said a rebel spokesman in London.