WASHINGTON/KABUL (Reuters) – The United States and Britain on Sunday launched a first wave of air strikes against Afghanistan and President Bush said the action heralded a ”sustained, comprehensive and relentless” campaign against terrorism.

Eyewitnesses said they saw flashes and heard explosions over the Afghan capital of Kabul in the first phase of what the United States has said will be a protracted and wide-ranging war against terrorism and the states that support it.

The attack had been prepared since the Sept. 11 suicide attacks on the United States that killed around 5,600 people.

In a televised address from the White House, Bush said the strikes against Afghanistan were carefully targeted at military installations and the United States would also be air dropping food to needy Afghan people to demonstrate that its war was not against them.

“These carefully targeted actions are designed to disrupt the use of Afghanistan as a terrorist base of operations and to attack the military capability of the Taliban regime,” Bush said.

“We are joined in this operation by our staunch friend, Great Britain,” he said, adding that several other countries had also pledged forces as the operation unfolds.

“Now, the Taliban will pay a price. By destroying camps and

disrupting communications, we will make it more difficult for the terror network to train new recruits and coordinate their evil plans,” Bush said.

He called on Americans and their allies to be patient, saying this war would not be over quickly. Initially, he said, Osama bin Laden — Washington’s prime target in the military strikes — and his terror network might be able to burrow deeper in caves and other hiding places.

“Our military action is also designed to clear the way for sustained, comprehensive and relentless operations to drive them out and bring them to justice,” he said.

The attack came hours after Washington rejected an offer from Afghanistan’s Taliban to put bin Laden on trial, a last-ditch effort to stave off U.S. military action.

The United States has accused bin Laden of masterminding last month’s attacks when hijackers took over passenger airliners and crashed them into New York’s World Trade Center and the Pentagon.

Bin Laden, 44, an extremist Islamic militant from a wealthy Saudi family, has been defying U.S. efforts to capture or kill him for years. Since 1996, he has been living under protection of the fundamentalist Taliban regime in Afghanistan in a remote mountain redoubt.

He has also been indicted for the deadly 1998 bombings of the U.S. embassies in Dar es Salaam, Tanzania, and Nairobi and was linked to last October’s attack on the USS Cole in Aden, Yemen, which killed 17 American servicemen.

A week after the attack on the United States, Bush presented the Taliban with an ultimatum, demanding that they surrender bin Laden and lieutenants in his al Qaeda network, close his training camps, allow international inspections, and release detained aid workers.

He said if they failed to comply, the Taliban would share the fate of the bin Laden network. The Taliban adheres to an extreme, puritanical form of Islam, under which women are not allowed to work, seek education or to show their unveiled faces in public.

Afghanistan’s opposition Northern Alliance said it had complied with a U.S. request to close its airspace and ground its small fleet of helicopters and fixed wing planes a few hours before the attack began.

It warned residents of Kabul to stay away from military installations.

The Taliban has been diplomatically isolated and is now almost encircled by hostile military forces as the assault began. Bin Laden has been living as a “guest” of the Afghan government since 1996.

Under intense pressure and with reports mounting of defections by some of its supporters, the Taliban is reacting with a mixture of defiance and attempts at conciliation.

The Taliban said an extra 8,000 troops were being sent to its northern border with Uzbekistan to join several thousand already there.

“We have deployed our forces there at all important places. This is the question of our self respect and we will never bow before the Americans and will fight to the last,” Afghan Islamic Press quoted a Taliban spokesman as saying.

Afghan opposition forces fighting the ruling Taliban said on Sunday they had seized 11 villages in the central province of Ghor and were advancing on the provincial capital Cheghcharan.

An opposition spokesman, Mohammad Habeel, said Taliban defections were partly responsible for the advance in Ghor, which followed reports on Saturday of similar movement in the northern province of Samangan.

“The probability of the fall of Cheghcharan is high,” Habeel told Reuters by satellite telephone.

The United States has sent 1,000 soldiers to Uzbekistan, which shares a border with Afghanistan and the Voice of America said the first planes had landed.

U.S. and British aircraft carriers, more than 300 warplanes, ships armed with cruise missiles and special forces troops gathered within striking distance of Afghanistan. Some 30,000 troops have also been deployed.

In Kabul, scores of people prepared to leave the beleaguered capital, a day after the sound of anti-aircraft guns trying to hit a circling spy aircraft renewed fears of imminent military strikes.

Security forces in Pakistan’s border province of Baluchistan ordered Afghan refugees to move from camps near the airport after intercepting a message threatening to down an airliner.

The United Nations says a quarter of Afghanistan’s 24 million population are dependent on food aid, that more than a million people have fled their homes within the war- and drought-ravaged country and that up to 1.5 million more may try to cross into neighboring countries.

Aid agencies stepped up their pleas for emergency food shipments to the country and Oxfam said between 1 million and 2 million people were already on the road in Afghanistan, trying to reach safety.