THREE British Muslims have been killed by US bombs while fighting for the Taliban, it was claimed last night.

The news came as Prime Minister Tony Blair called for the British people to hold their nerve amid growing concern over mounting civilian casualties in Afghanistan.

Aftab Manzoor, 25, and Afzal Munir, in his early 20s, both from Luton, Bedfordshire, and Yasir Khan, from Crawley, Sussex, were killed during US bombing raids on the Afghan capital of Kabul on Wednesday.

Two American Muslims who had joined the Taliban were also killed.

Confirming the deaths, Hasan Butt, leader of the al-Muhajiroun in Lahore, Pakistan, said: "All of them had gone to Afghanistan in early October to wage jihad against the unjust policies of America."

Muslims in Luton reacted with shock yesterday, amid fears among the town's 20,000-strong Muslim community of a racist backlash.

In Afghanistan, 13 civilians, including at least seven children, were reported to have been killed yesterday during early-morning air strikes on Kabul, at the end of one of the heaviest nights of bombing since operations began.

The deaths came a day after ten villagers died when a stray bomb hit a house in territory held by the rebel Northern Alliance.

And in Pakistan, tensions were running high after 16 Christians were massacred in a hail of bullets by gunmen as they attended a service in the town of Behawalpur.

But in a move calculated to stiffen resolve among the British public, the Prime Minister issued a plea for patience and vowed to continue military action for as long as it took to make the world safe from terrorism.

Downing Street insisted that the military campaign had achieved notable successes against Osama bin Laden's al Qaida terror network and the Taliban regime, and added that Mr Blair was determined not to be blown off course by demands for instant solutions.

Mr Blair's official spokes-man said last night: "The Prime Minister believes the country recognises that this is a campaign which will take both time and patience.

"In any campaign, there are times when things go well and times when things go less well. What is important is that we keep our eye on the main objectives and continue our efforts to complete them."

Mr Blair is expected to use his speech tomorrow to the Welsh Assembly to drive home the need for patience and resolve.

The Prime Minister won support from Tory leader Iain Duncan Smith, who said the killings in Pakistan should not deflect from the task of bringing Osama bin Laden to justice.

President Bush's special envoy, Richard Haas, said the air strikes had been more than 99 per cent effective and echoed Mr Blair's call for patience.

He said: "The fact that it is not going to be quick and easy should not come as any surprise. We are only weeks into the military effort. It has obviously got some ways to go."

However, there were growing signs yesterday of some strain within the coalition.

Pakistan's President, General Pervez Musharraf - a key member of the coalition against terrorism - voiced his concern over the growing numbers of civilian deaths.

Following a meeting with German Chancellor Gerhard Schroeder, he said: "We feel the military action should possibly be short and targeted in order to avoid civilian casualties."

He spoke as hundreds of armed pro-Taliban Pakistanis seized a remote northern town and demanded that the government should stop supporting the US-led strikes.

A leading North-East academic warned yesterday that westerners may not have the stomach for a long war in Afghanistan because of what he termed "fast-food culture".

Durham University politics lecturer Dr Mark Aspinwall said society on both sides of the Atlantic has become a slave to immediacy and convenience, which would be reflected in people's perception of the conflict.

Meanwhile, former Labour defence minister Peter Kilfoyle warned of confusion in the Government over the ineffectiveness of air strikes so far, while former MP Tony Benn denounced what he said was an "immoral" war in which children were dying.

Mr Kilfoyle called for a halt to the bombing, saying: "It's bound to cause indiscriminate damage to those innocent people who have been subject to the Taliban and many other degradations down the years.