Muslims have been told it is their "Islamic duty" to co-operate with the police to ensure Britain's safety.
Regent's Park mosque was the setting for the "lively" meeting
The statement was agreed at a "deeply significant" meeting in London held by the Muslim Council of Britain.
More than 200 people, including imams, community activists and police representatives, gathered to lay out ways to combat the threat of terrorism.
A spokesman said there was a real willingness to accept the "problem within the Muslim community".
Media were excluded from the "lively" two-and-a-half hour meeting, but Inayat Bunglawala, from the Muslim Council of Britain (MCB), spoke to the BBC News website afterwards.
He said: "One of the key factors that we are agreed on is that there's an Islamic duty to co-operate with the police to ensure the safety of British citizens - Muslims and non-Muslims."
The problem, he said, lay with a small number of extremists who shared a "violent world view" and who are "killing civilians for what they believe is an interpretation of Islam".
Mr Bunglawala added that leading imams at the meeting called it a "lethal misinterpretation".
In addition to the cultural impact of the alleged bomb plots in Glasgow and London, the meeting also discussed the effects of foreign policy on fundamentalism.
Mr Bunglawala said: "Some naturally raised the issue of foreign policy and we agreed our actions overseas have inadvertently helped the spread of extremist ideas."
At the meeting, held at the Islamic Cultural Centre next to Regent's Park mosque, MCB secretary general Dr Muhammad Abdul Bari said: "These people who attempt to kill or maim in this way are enemies of us all."
The meeting was also attended by Metropolitan Police Commander Simon Foy, who said the police had a "responsibility" to let the Muslim community do its own work in tackling extremism rather than officers adopting a heavy-handed approach.
'Lackeys and bootlickers'
A declaration on tackling Islamic extremism and terrorism in Britain followed the meeting.
Statements included "all Britons - Muslim and non-Muslims - should stand united against the threat of terrorism", and "Islam requires us to protect and safeguard the life of civilians".
The declaration also said: "As citizens we will address international issues of concern by promoting political engagement of our people in the democratic processes".
Outside the centre, some protesters had gathered and accused the organisers of being "lackeys" and "bootlickers" of the "Blair/Brown regime".
The opening speeches of the conference were in full swing when shouting was heard from outside the conference from the group of young men.
They were opposed to the meeting's call for co-operation with the police, and they were kept out because of fears they were planning to disrupt the meeting.
"We don't like what they're doing in there, asking people to work with the Metropolitan Police," said one.
Mohammed Shafiq, from the Ramadan Foundation, which took part in the conference, told BBC News it was important to reach such disaffected young Muslims.
"We've got to keep on engaging with these people, trying to convince them that their path is the wrong path," he said.
"Our path is the mainstream of Islam. Islam totally condemns violence - it's forbidden in Islam and that's unanimous."
Another participant in the meeting, Mohammed Khaliel, said: "Foreign policy was mentioned over and over again. Whatever the government or some MPs say, it is a factor that is fuelling extremism."