EVEN as the Ethiopian Army began its assault this weekend on the "final" stronghold of the Islamists who have ruled Somalia for the past six months, the defeated faction was already reverting to a guerrilla war that will mean yet more suffering for people in the Horn of Africa.

Ethiopian soldiers, backed by tanks, armoured cars and jet-fighter-bombers, are pursuing hundreds of Islamist fighters into the dense Ras Kamboni mangrove forest at the southern tip of Somalia between the Indian Ocean coastline and the Kenyan border.

Here the Ethiopians hope to declare victory for Somalia's fragile, secular, unelected Transitional Federal Government (TFG) - which has the seal of approval of the African Union and the United Nations - over the Union of Islamic Courts, which has ruled the country since June.

But the Ethiopians will inevitably find that their two-week-long blitzkrieg has been the easy part of the pacification of Somalia, whose new interior minister, Hussein Farah Aideed, son of a notorious warlord, admitted: "We have only a symbolic government. Ministries we don't have, a military we don't have. We're limited."

Aideed's father, the late Mohammed Farah Aideed, was targeted by US soldiers in a failed raid in 1993 that led to the ignominious deaths of 18 American troops and the US withdrawal from Somalia. The rusted parts of the US Black Hawk helicopters shot down in that incident still lie on the ground in Mogadishu, the Somali capital.

African analysts are asking: does Meles Zenawi, Ethiopia's prime minister, think he is Africa's George W Bush?

"We're going to turn this place into another Iraq," construction worker Abdullah Hashi said in reaction to the entry of Ethiopian troops into Mogadishu. Hashi said he was a member of a new anti-Ethiopian underground, with many other signs of an emerging resistance by Somalis who, whatever their differences, are generally united by dislike of neighbouring Ethiopia. Masked gunmen, shouting anti-Ethiopian slogans, are already emerging on the streets of the capital, a sure sign that a classic guerrilla resistance is underway.

Tajudeen Abdul-Raheem, a Uganda-based political analyst and deputy director (Africa) for the United Nations' Millennium Campaign, said: "If a country with almost 100% Muslims wants to be governed Islamically, how undemocratic is this the overthrow of the Islamic Courts administration? Does Meles not realise that the Transitional Federal Government will remain a puppet regime?"

The comparison with Iraq is inevitable, but the Ethiopians and the TFG face a problem that the Western allies in Iraq did not: the West toppled Saddam Hussein who was widely hated, but the Union of Islamic Courts enjoyed more support among Somalis than any other of their rulers in past decades. Though the puritanical courts frowned on films, dancing and music - widely enjoyed by Somalis, who tend to interpret their Islam liberally - the people of the towns welcomed the fact that life was safe under the courts' rule. People put away their guns, but they are again unlocking them in anticipation of anarchy.

People threw support, whether reluctantly or enthusiastically, behind the Islamists because they established order, replacing the warlords who ruled by thuggery, threats and bribes. The courts managed to get the country's economy moving again, reopening Mogadishu's airport and seaport after they had been closed to commercial traffic for more than 11 years.

WITH Somalia fundamentally unstable, with many weapons still in the hands of warlords, divided into complex clans, subclans and sub-subclans, it is totally unclear how the TFG intends to establish its writ. The task is daunting. The TFG has somehow to try to piece together a country that has not had a functioning government for 15 years. Those years have been marked by the fall of a dictator, general Mohammed Siyad Barre, followed by a civil war; the rise of a coalition of warlords; the failed US intervention; the overthrow of the warlords by the Islamic Courts; and now the arrival of yet another foreign army from a hated neighbour.

Among the most important subtexts of the saga is the suspected presence in Somalia of at least three al-Qaeda-linked operators accused of involvement in the 1988 bombings of US embassies in Kenya and Tanzania and attacks on other Western targets. This explains US support for Ethiopia's invasion; the presence of the US 5th Fleet, normally based in Bahrain, off the Somali coast; and reports by intelligence sources that US special forces are operating on the Somalia-Kenya border.

The Ethiopian-US grand design looks like turning into a very long war. High-level negotiations have begun to send in an African Union peacekeeping force. But given the failure of underfunded and undersupplied AU peacekeepers in Darfur, it is hard to see why they can hope to succeed in the even more fearsome cauldron of Somalia.