Islamic militants in Somalia are asking foreign Muslim fighters to join what they call a "holy war" against government troops backed by Ethiopia.
Islamist defense chief Yusuf Mohamed Siad appealed for foreign help Saturday as more fighting was reported between rival forces.
Witnesses say they heard artillery fire near the town of Baidoa, where the interim government is based. The two sides claim to have killed hundreds of enemy fighters in recent clashes in southern Somalia.
In Cairo, Egypt's government and the Arab League called for an end to fighting. They warned of a possible regional conflict.
Somalia's Prime Minister Ali Mohamed Gedi urged Islamist leaders to return to peace negotiations.
Government forces have little influence outside their base in Baidoa, while Islamist forces have seized much of southern and central Somalia.
Islamist leaders have threatened to attack Ethiopian troops if they do not leave Somali territory. Ethiopia has an undetermined number of soldiers in Somalia to assist the interim government.
Some information for this report was provided by AFP and Reuters.