HEADS bowed in sorrow, faces a mixture of shock and grief, the 1,000-strong congregation listened in silence as they heard prayers for those killed in the terrorist attack on the United States, as well as for the grieving relatives.

But, along with the emotions shared by millions of people across the country, anxiety was also etched into the faces of worshippers at Middlesbrough's Jamia mosque.

Within hours of the first jet hitting the World Trade Centre, the finger of suspicion had already pointed at Islamic extremists, a feeling only strengthened over the succeeding days. As each new sliver of evidence emerges, the belief grows that Saudi millionaire Osama bin Laden is responsible for the atrocity.

And, with this belief, has come ever-louder calls for retribution, for vengeance against those to blame for the worst terrorist outrage in history. But this, in turn, has provoked fears that the retaliation, when it comes, will, like the terrorists themselves, not discriminate between innocent civilians and military targets. And not only in bin Laden's Afghanistan refuge: there have already been reports of hostility towards Muslims in Britain and the West.

For the Muslims gathering at the Jamia mosque for the main 2pm prayers yesterday, the words of the Imam captured their response to the tragedy, according to a mosque committee spokesman. "The Imam spoke of our condolences and we prayed for the victims, for their families and everybody concerned," he says.

"Don't forget that there were Muslims and Hindus and Christians in there. I hope that our local society realises that this is not something instituted by the community at large, is not instituted by Muslims, not by Pakistanis or the Arabs, but this is terrorism, which is condemned by all religions.

"It has nothing to do with religion. No religion calls for innocent lives to be taken away. If anybody is portraying this as an act by Muslims or the Arabs that is not true. You cannot make the whole nation or the whole religion responsible for the actions of one or two individuals."

But, he says, there is a fear that previous harmonious relations between the different communities could be damaged by the actions of a small group of extremists and of widespread calls for retribution. And there is also a belief that any retribution should not be directed against, or include, innocent civilians, and that answering violence with violence will only ensure a constant and self-perpetuating cycle of death and destruction.

"Any talk of violence against civilians, be it by an individual, a religious organisation, a Government - and that includes America, Britain or the Middle Eastern countries - should be condemned," he says. "The poor of Afghanistan didn't bring about Osama bin Laden, they don't deserve to be shot at and bombed. Wherever there is war there are civilians involved, and that is very unfortunate. That is what worries me, that is my prime concern.

"I hope the world is trying to look into the root of this problem. You kill one terrorist, there is another one being born, it is not the end of it. If they get Osama bin Laden, is there somebody else ready to take his place? What is the point of getting one terrorist, if they then take away the lives of 10,000 more? Is it worth the total? There needs to be a permanent settlement, and we have to get to the root of it."

Increasing tension has already forced the first state-funded Islamic school, in Brent in London, to close, to ensure its pupils are not harassed or attacked. The school has received threatening phone calls in the aftermath of the atrocity and the school secretary was verbally abused in the street.

In Belfast, bricks have been thrown at a mosque, and in the US bomb scares have forced Arab-American schools and businesses to close. Perhaps the most horrifying story of retribution has been reports of the stoning of a school bus full of Muslim children in Brisbane in Australia.

"There is tension and there could be problems," according to Tahir Khan, chairman of the Unity Organisation Multicultural Centre in Sunderland. "There is nothing to say there are not extremists in this country who will not try and take revenge, but they will be wrong.

"I don't think in Britain and America that the ordinary people should be harmed, but there are opportunists who are already looking trouble. People like the BNP or the National Front, they are the ones who might try to stir trouble and cause harm.

"People like myself, who have lived our lives here, have done no harm to anybody. The ordinary citizens here are not into politics, we're not extremists, we have no interest in that."

He says the Muslim community shared the reaction of the rest of the British population to the atrocity, but with an added emotion. "As a Muslim I was horrified, and ashamed," he says. "No religion allows you to attack innocent people.

"Whoever did this, I don't class them a Muslim. My feeling is, if they did this under the name of Islam, it was not a religious war. They had no right whatsoever to kill innocent people.

"I have all the sympathy for the victims, and my condolences to the American people, and to the British and any other nationality who have lost their beloved ones. The people responsible have to be brought to justice."

But any retaliation, he says, should be directed at those responsible, and not simply at the wider target of Muslims, or even Afghanistanis. And, he adds, many Muslims in Britain will support this aim.

"If the British Government asked for my services, I would help however I could. I don't care if I have got to go and fight Muslims face to face. I feel, as a British Muslim citizen, this is the land I have to protect," he says. "I was born in Pakistan, but if I were to go and fight for Britain, it is my land and I would be honoured to do that. Many Muslims will feel the same.

"We have to identify whoever is responsible and bring them to justice, and that does not mean the Muslim people are punishable. The ordinary people have nothing to do with these extremists, we should leave the innocent people alone. Two wrongs do not make a right. Instead of making it worse, we should be working together to make it better."