Osama bin Laden's deputy has called on Somalia's Islamic militants to carry out suicide attacks on Ethiopian troops fighting in their country, according to a taped message posted on the internet Friday.

Al-Qaeda's No. 2 also implores Muslims worldwide to support Somalia's Islamists with fighters, money and expertise.

"I speak to you today as the crusader invader forces of Ethiopia violate the soil of the beloved Muslim Somalia," Egyptian-born Ayman al-Zawahri said in the recording.

Ethiopian-backed government forces have driven the militants from the capital Mogadishu and much of southern Somalia, ending their six months in power. Many Islamists have retreated to the southern tip of the country where they have vowed to keep fighting, raising the spectre of an Iraq-style guerrilla war.

"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 said. 

"Launch ambushes, land mines, raids and suicidal combats until you consume them as the lions and eat their prey," he added. 

The message could not immediately be authenticated, but it aired on an Islamic website known for publishing militant material and carried the logo of al-Qaeda's media production wing, al-Sahab.

Ethiopia is a Christian country long despised in Muslim Somalia. The countries have fought two wars, the most recent in 1977, and Somalia lays claim to territories in Ethiopia. Ethiopia is also a U.S. ally and American naval forces are deployed off the Somali coast to prevent the militants from fleeing by sea.

Three al-Qaeda suspects wanted in the 1998 bombings of U.S. embassies in East Africa are believed to be leaders of the Islamic movement in Somalia. The Islamists deny having any links to the terror network.

Al-Zawahri reminded the militants that the U.S. and United Nations were previously defeated in Somalia.

In 1992, a United Nations peacekeeping force, including U.S. troops, arrived in Somalia but the experiment in nation-building ended the next year when fighters loyal to a Somalian clan leader shot down a U.S. Army Black Hawk helicopter and battled American troops, killing 18 servicemen.

"My brother Muslims in Somalia, don't be traumatized by America's force because you have defeated it previously with the support of Allah, and it is weaker today than before," al-Zawahri said in the audiotape.

The recording, which lasts more than five minutes, is the first al-Zawahri has issued this year. He issued 14 taped statements last year.