Demonstrations by far right activists fuel Islamic extremism, police said today.
The actions of groups such as the English Defence League can provide opportunities for recruiting Muslims to radicalism, according to counter-terrorism officers.
Since the EDL emerged last summer it has held demonstrations in towns and cities against Islamic extremism, with another planned for Preston city centre on Saturday November 27.
But the West Midlands counter-terrorism unit said there is evidence that violence or damage towards Muslim property associated with EDL demos encourages extremist retaliation afterwards.
Detective Superintendent John Larkin told BBC Radio 5 Live: "They look for the hook to pull people through and when the EDL have been and done what they've done, perversely they leave that behind."
Another officer said extreme sections of the EDL attacking Muslims provide "constituent parts" for those who would radicalise vulnerable people to encourage them to "go through the gateway towards being radicalised".
Matthew Feldman, lecturer in 20th century history at Northampton University, told the programme the EDL grew out of a "tit-for-tat kind of extremism and radicalisation".
He added: "We see a very exacting example of just how symbiotic some of these types of radicalisation can be."
Policing minister Nick Herbert told 5 Live: "Violence and intimidation are highly unacceptable, wherever it comes from.
"You can't tackle extremism by being extremist yourself. You don't prevent hatred by being hateful yourself."
Lancashire Constabulary said they are working hard to ensure the Preston EDL demo - which is likely to attract a counter event from Unite Against Fascism - causes minimum disruption.
Police and council chiefs want people to be able to go about their daily business in the city despite the gatherings, which have caused flashpoints at similar events elsewhere in England.
Chief Superintendent Tim Jacques, divisional commander for central division, said: "We want to make sure that Preston remains open for business as usual on the day and that there is no disruption to daily life, although obviously there will be a highly visible police presence throughout the day."