Speaking about the murder of Drummer Lee Rigby in Woolwich, Labour leader Ed Miliband said extremists will fail to divide Britain because "British people know this attack did not represent the true values of any community, including Muslim communities who contribute so much to our country".
Mr Miliband said he supported action to bring the perpetrators to justice and work to unite communities and learn the lessons of the attack.
But he questioned the Prime Minister on whether the events in Woolwich would mean further movement on controversial communications data proposals.
Mr Miliband said, "What is your current view on the need for legislation on communications data?"
Mr Cameron replied: "I think we need a frank debate in this House. There is a problem when, at the moment, some 95% of serious crimes involve the use of communications data.
"That is not the content of a fixed or mobile telephone call, it's about the nature of the call - when it was made, who was it that made it, when did they make it".
Prime Minister David Cameron has chaired the first meeting of a new task force, known as TERFOR, which aims to tackle terrorism and religious extremism.
The task force agreed to tackle all types of extremism "head on" following the murder of Drummer Lee Rigby.
A Number 10 spokesman said: "The Prime Minister tasked Ministers to work on practical suggestions which the task force could discuss at future meetings.
"He asked Michael Gove and David Laws to look at confronting extreme views in schools and charities, with Vince Cable looking at universities; Chris Grayling to look into similar issues in prisons; and, Baroness Warsi to look at work in communities".
Ministers at today's meeting included Chancellor George Osborne, Deputy Prime Minister Nick Clegg, Home Secretary Theresa May and Education Secretary Michael Gove.
In a speech in the House of Commons David Cameron paid tribute to the security services and also vowed that the government will not stand for extremists or, "groups like the English Defence League who try to demonise Islam and try and stoke up anti-Muslim hatred."
The police and security services will not rest until they have brought all those responsible to justice.
Already this year there have been three major counter terror trials in which 18 people were found guilty and sentenced to a total of 150 years in prison much more of the British security services necessarily goes unreported. They are Britain's silent heroes and heroines and the whole country owes them an enormous debt of gratitude.
Just as we will not stand for those who pervert Islam to preach extremism, neither will we stand for groups like the English Defence League who try to demonise Islam and try and stoke up anti-Muslim hatred by bringing disorder and violence to our towns and cities.
Speaking to the House of Commons the Prime Minister has said:
"What happened on the streets of Woolwich shocked and sickened us all. It was a despicable attack on a British soldier who stood for our country and our way of life and it was too a betrayal of Islam and of the Muslim communities who give so much to our country.
"There is nothing in Islam that justifies acts of terror and I welcome the spontaneous condemnation of this attack from Mosques and community organisations right across our country."
Prime Minister David Cameron will make a Commons statement this afternoon about the death of Drummer Lee Rigby, when MPs return from their half-term break.
Mr Cameron will make the address after chairing the first meeting of TERFOR, an anti-terrorism task-force set up in the wake of the Woolwich attack.
Mr Cameron cut short an official visit to Paris on the day of Drummer Rigby's death to return to the UK for a meeting of the Government's emergency Cobra committee and made a statement outside 10 Downing Street.
David Cameron will today chair the first meeting of a new anti-terrorism task force, set up as a result of the Woolwich killing.
The Cabinet level group, which will also bring in intelligence and police chiefs when needed, will focus on radical preachers who target potential recruits in jails, schools, colleges and mosques.
It will monitor trends in radicalisation and tackle "poisonous narratives", Number 10 said.
Other members include Deputy Prime Minister Nick Clegg, Home Secretary Theresa May, Chancellor George Osborne, Metropolitan Police commissioner Sir Bernard Hogan-Howe and Andrew Parker, the director general of the Security Service.
Downing Street said it would be an "exploratory meeting".