In Afghanistan, the resurgent Taliban are retaking villages and expanding their influence in the southern provinces of Kandahar and Helmand. This summer, a NATO force of 6,000 men, under the command of a British general, David Richards, is being deployed to the area in the hope of regaining the initiative. But it will undoubtedly face attack from Taliban suicide bombers, attrition from roadside bombs, as well as ambushes. It may even have to fight pitched battles with increasingly daring and well-armed Taliban guerillas.

More troublesome for Washington is the growing disillusion of the population with President Hamid Karzai and his Western backers. Even in the capital Kabul - hitherto the only reasonably secure place - recent explosions of anti-American violence suggest there is now little support among the population for the American-backed government. Karzai himself is increasingly seen as a US puppet.

A major grievance is that Western aid money which has poured into the country has so far brought little perceptible benefit to ordinary people, who continue to suffer from poverty, unemployment, bad government and widespread corruption.

Last year, the Taliban killed more than 300 government soldiers and US-led coalition troops. This year, the toll is likely to be higher still.

Somalia is proving an even greater challenge to the United States than Afghanistan. The coalition of Somali warlords the US has been financing - the so-called Alliance for the Restoration of Peace and Counter-terrorism - was routed last week by a militia owing allegiance to the Union of Islamic Courts.

The US-backed warlords were kicked out of the capital Mogadishu, and are now in danger of being expelled from their last stronghold, the town of Johwar, some 100 kilometres further north.

These gains by the Muslim militia mark the climax to four months of bitter fighting. They promise to be a measure of peace and security to the hard-pressed country for the first time in fifteen years.

Civil war broke out in Somalia in November 1991, some months after the ousting earlier that year of President Muhammad Siad Barre, a sanguinary despot who had ruled the country since 1969. Various attempts by the international community to end the civil war were unsuccessful.

In 1994, the United States pulled its troops out hastily after attempts to capture the warlord Muhammad Farah Aidi ended in disaster and the death of 18 American troops. That year, a transitional federal government failed to establish itself in the capital.

In the past year, the United States - through the CIA station in Nairobi - started sending hundreds of thousands of dollars to Somali warlords who, it was hoped, would kill or capture suspected members of al-Qaeda, and prevent Somalia becoming a safe haven for Taliban-style fundamentalists.

Ever since the bombings of the US embassies in Kenya and Tanzania in 1998, American intelligence agents have tried to find and destroy al-Qaeda cells in East Africa, but so far with only limited success.

Last February, with American encouragement and finance, eleven warlords formed the so-called Alliance for the Restoration of Peace and Counter-terrorism. Their aim was to counter the rising power of the Islamists.

Some observers believe, however, that the American intervention on the side of the warlords may have prompted the Islamists - and especially the Union of Islamic Courts - to form, expand and arm their own militia. It is now estimated to number about 3,000 men. Both sides are said to have spent up to $45m on weapons in recent months.

Following an offensive of less than four months, the militia of the Union of Islamic Courts captured Mogadishu on 5 June, after a battle which killed 350 fighters and wounded another 1,500. The warlords and their business partners fled.

The Union of Islamic Courts is chaired by Shaikh Sharif Ahmad, a former teacher in a Quranic school. In recent statements, he has hinted that his movement might consider establishing an Islamic Republic in Somalia, but he invariably adds that this would depend on "the will of the people."

Other more powerful figures in the Islamic movement include Shaikh Yusuf Indahadde, a rich businessman who assembled a large number of pick-up trucks which played a key role in the recent fighting, and Shaikh Hasan Dahir Awais, who is thought to be a leading military strategist of the Union of Islamic Courts.

The upshot of the battles in Somalia will encourage Islamic forces and movements in the Horn of Africa and throughout the Middle East. The US policy of counter-terrorism has suffered a serious setback which is likely to have repercussions throughout East Africa and beyond.