Al-Qaida's deputy leader urged Somalia's Islamist guerrillas to remain steadfast in their battle against "invaders" and crusaders," according to an Internet audiotape released Friday. Somalia's Islamic Courts rebels were resoundly beaten by pro-government and Ethiopian troops earlier this week and chased from the capital, Mogadishu. Somali and Ethiopian soldiers on land and US troops at sea have also surrounded hundreds of the Islamic movement's militiamen on the southern tip of the country. "I speak to you today as the crusader invader forces of Ethiopia violate the soil of the beloved Muslim Somalia," Egyptain-born Ayman al-Zawahri said in the audiotape. "I call upon the Muslim nation in Somalia to remain in the new battlefield that is one of the crusader battlefields that are being launched by America and its allies and the United Nations against Islam and Muslims," al-Zawahri added. The more than five-minute audiotape could not immediately be verified but was aired on a Web site frequently used by militants and carried the logo of al-Qaida's media production wing, al-Sahab.