David Cameron has set out the government's strategy to defeat the "poison" of Islamist extremism.
He pledged to tackle extremist ideology and "the failures of integration" which he said had led to hundreds of Britons joining Islamic State (IS) militants.
Among a number of proposals, the PM promised to allow parents to have their children's passports cancelled if they feared they were at risk.
He also pledged to look at social housing to prevent further segregation.
The Muslim Council of Britain urged the prime minister to "put his words into action" and engage with "all sections of the community including mainstream Muslim organisations and those who have differing views".
'Sick world view'
In a speech in Birmingham on the government's five-year plan to defeat home-grown extremism, Mr Cameron set out four major areas that needed attention: countering the "warped" extremist ideology, the process of radicalisation, the "drowning out" of moderate Muslim voices, and the "identity crisis" among some British-born Muslims.
He said the focus of his speech was Islamist extremism - not Islam the religion - and that moderate Muslims also hated the "sick world view" of extremists.
"I want to work with you to defeat this poison," he said.
He said the government's strategy included plans to:
- Strengthen communications watchdog Ofcom role to take action against foreign TV channels broadcasting extremist messages
- "Incentivise" schools to become more integrated
- Demand that internet service providers do more to remove extremist material and identify those responsible for it
- Overhaul the strategy to tackle extremism in prisons
- Consult on introducing lifetime anonymity for the victims of forced marriages
- Create a new review by civil servant Louise Casey into boosting opportunity and integration for minority groups
- Urge universities to do more to challenge the views of extremist speakers
- Set up a new engagement forum
- Launch a study looking at how extremism spreads
He spoke about a lack of confidence when it came to enforcing British values, referring specifically to forced marriage and female genital mutilation.
"No more turning a blind eye on the basis of cultural sensitivities," he said.
Analysis by Norman Smith, BBC assistant political editor
"No-one becomes a terrorist from a standing start," said the PM.
And in that one phrase lies the core of Mr Cameron's argument: people become terrorists gradually.
They start with intolerant views towards democracy, freedom of expression and sexual equality. If this is not challenged they often gravitate to even more extreme views.
And this over time can lead to violence and terrorism.
In other words, tackling the ideology of IS involves confronting people over intolerance, prejudice and hostility to British values.
How to do this is much more fraught and Mr Cameron today came forward with relatively few specific policies. Why?
In part because of the fear of a backlash from the Muslim community.
But also because of an understandable wariness of compromising freedom of speech and expression - precisely the values Mr Cameron wants to defend.
The prime minister said the UK needed to "de-glamorise" the extremist ideology and conspiracy theories used by groups such as IS.
"This is a group that throws people off buildings, that burns them alive... This isn't a pioneering movement, it is a vicious, brutal and fundamentally abhorrent existence," he said.
Keith Vaz, the Labour chairman of the Commons Home Affairs committee, said the government needed to engage with Muslim communities.
"We need to understand why a few become isolated from their own communities," he said.
BBC home affairs correspondent Daniel Sandford said giving worried parents the power to have their children's passports removed was a concrete step.
At present, children can be made a ward of court and then the local authority can prevent them travelling, or parents can go to the police who could act in certain circumstances, he said.
Our correspondent said the emphasis of Mr Cameron's speech was on the "battle of ideas" but added it could be about 10 years too late.
"The people they have to persuade are the young people who are already, to a degree, lost - and that is a big challenge for the government," our correspondent said.
Tracking Britain's jihadists
The stories of those who have died, been convicted of offences relating to the Islamic State conflict or are still in Syria or Iraq.
Mr Cameron said it was not enough for groups to say they opposed IS.
This would be setting the bar for acceptability "ludicrously low", and groups should be expected also to condemn conspiracy theories, anti-Semitism and sectarianism, he said.
The Extremism Bill, unveiled in the Queen's Speech to Parliament in May, will include "narrowly-targeted" powers to tackle "facilitators and cult leaders" and stop them "peddling their hatred", said Mr Cameron.
While welcoming aspects of Mr Cameron's speech, the Ramadhan Foundation said "there was a lot about what he thinks and believes but with very little substance on what he is going to do".
Chief executive Mohammed Shafiq also rejected Mr Cameron's use of the term "grievance justification", whereby he said some people blamed the rise of extremism on "historic injustices, recent wars, poverty and hardship".
He said the PM's idea that "somehow we're saying foreign policy is an excuse is really offensive".
Dr Shuja Shafi, secretary general of the Muslim Council of Britain, said the group agreed with the prime minister that Islamic State's causes must be de-glamorised.
"We worry, however, that these latest suggestions will set new litmus tests which may brand us all as extremists, even though we uphold and celebrate the rule of law, democracy and rights for all," he said.
"Dissenting is a proud tradition of ours that must not be driven underground."
In his speech, Mr Cameron attacked the National Union of Students for "allying itself" with the advocacy group Cage.
But the NUS responded by saying it would not work with Cage "in any capacity".
The government is expected to set out a wider counter-extremism strategy later this year which will include more legislation.
Police and security services believe at least 700 extremists have travelled to fight with IS militants who have taken control of large swathes of Iraq and Syria, with half since returned and posing a domestic terror threat.
Meanwhile, Defence Secretary Michael Fallon has told MPs that five RAF pilots have been embedded with coalition forces carrying out air strikes against IS in Syria in the past year.
Parliament has approved UK involvement in air strikes in Iraq and Mr Cameron has suggested he could soon seek approval to extend the military action to Syria.