"These evil deeds make victims of us all," the Muslim Council of Britain said in a statement on Thursday.
"The evil people who planned and carried out these series of explosions in London want to demoralise us as a nation and divide us as a people. All of us must unite in helping the police to capture these murderers," it said.
British Prime Minister Tony Blair said he welcomed the council's statement.
"We know that these people (perpetrators of the blasts) act in the name of Islam, but we also know that the vast and overwhelming majority of Muslims, here and abroad, are decent and law-abiding people who abhor this act of terrorism every bit as much as we do," he added.
Some London Muslims said they feared they would be targeted as a result of the explosions.
"Everyone is subdued, and people are wondering what has happened. People are asking how will it affect us, are we going to be treated in a nice way after this?" restaurant manager Karim Mohammed said. "We have nothing to do with this."
However, the British branch of the Islamist movement Hizb ut-Tahrir warned Muslims against blaming fellow believers for the bomb attacks.
"Condemnation with scant information will only aid the leaders of the West who want to use fear as a tool as well as allow them to arrest more Muslims unjustly under draconian terror laws," it said in a statement on Thursday.
Some London Muslims fear they
will be targeted after the blasts
"Yes, the rules of Islam do not allow the harming of innocent civilians, but at the same time the rules of Islam do not allow us to condemn Muslims with little evidence in order to remove the pressure from ourselves."
The organisation criticised the Group of Eight leaders meeting in Gleneagles, Scotland.
"The world's leaders congregating at the G8 summit in Gleneagles have quickly taken the opportunity to further their rhetoric to justify their 'war on terror'," the statement said.
The group told British Muslims to beware of revenge attacks after the blasts.
"It is possible in the days ahead that symbols of the Muslim community such as mosques and schools may be targets for vandalism," it said.
"It is also foreseeable that our Muslim sisters may be at the forefront of verbal abuse or even attack."
In his reaction, controversial UK lawmaker George Galloway said Londoners had "paid the price" for Britain sending soldiers into Iraq and Afghanistan and warned there was more to come.
Galloway(C) said the blasts were
despicable but predictable
"We argued, as did the security services in this country, that the attacks on Afghanistan and Iraq would increase the threat of terrorist attack in Britain," Galloway said in a statement on Thursday.
Later, the Respect Party MP told parliament the attacks were despicable but entirely predictable.
"Let there be no equivocation: The primary responsibility for the bloodshed this morning lies with those who carried out the acts.
"But it would be utterly crass to ... separate these acts from the political backdrop against which they took place.
"They did not come out of a clear blue sky, any more than those monstrous mosquitoes that struck the twin towers and other buildings in the United States on 11 September 2001."
A fierce critic of the March 2003 US-led war to remove Saddam Hussein, Galloway was expelled that year from Prime Minister Tony Blair's governing Labour Party, which he had represented in parliament since 1987.