The far right: BNP and EDL mobilise as mainstream leaders strive to contain backlash

Extremist groups plan rallies as fears of revenge attacks grow

Fears of a backlash against Muslim communities were rising last night despite attempts to calm anger at the savage killing in Woolwich.

David Cameron was among the politicians and community leaders who spoke out to describe the killing of Drummer Lee Rigby as a "betrayal of Islam" as much as it was an attack on the British way of life.

But the shocking brutality of the soldier's death has been seized upon by far-right groups as justification for their anti-immigrant and anti-Islam views. Those hoping to stoke religious and racial tensions include the English Defence League (EDL), which is planning a demonstration in Newcastle this weekend.

Dozens of the far-right group's supporters – many in hoods and balaclavas – clashed with police and local people after gathering outside the Queen's Arms pub in Woolwich on Wednesday night. Its leader Tommy Robinson told the crowd: "There has to be a reaction, for the Government to listen, for the police to listen, to understand how angry this British public are." Nick Griffin, leader of the British National Party, has announced plans to stage a demonstration in Woolwich on Saturday next week, under the banner "United Against Muslim Terror".

Muslims and Nigerians living close to the scene of the killing have raised concerns that they fear revenge attacks and Tell Mama, an organisation which monitors anti-Islam hate, reported a sudden rise in public and online calls for violent retribution.

Lucky Awale was among those living in the area who fears a backlash. "We are just asking for people not to take the wrong impression, the wrong idea, and take revenge on Muslims," she said. On Wednesday night a man was arrested in Braintree, Essex, after it was alleged he walked into a mosque armed with a knife and threatened to set it alight. A mosque in Gillingham, Kent, suffered criminal damage.

While most politicians were quick to say that Islam was not responsible for the killers' actions, former Home Secretary Jack Straw urged British Muslims to help root out the corrupted ideology that inspired such "Stone Age savagery".

"We can't ignore the fact that, in this century, most religious-based terrorism draws its justification from a distorted view of Islam," he said on BBC Radio 4's World At One. "In other centuries it was Christianity or Hinduism… However it's just a fact of life that extreme versions, not of Christianity, Judaism or Hinduism, but of Islam are used as justifications for this kind of terrorism. We have to have that dialogue within the community."

Mr Cameron responded to fears of a backlash when he emerged from a Cobra meeting by praising the role of Muslims in Britain and saying they shared the anger and disgust at the killing as much as anyone else.

"This was not just an attack on Britain and on the British way of life, it was also a betrayal of Islam and of the Muslim communities who give so much to our country. There is nothing in Islam that justifies this truly dreadful act," he said. His sentiments were echoed by Ed Miliband, the Labour leader: "There will be people who try to use events like this to divide us and they will fail too."

Boris Johnson, the Mayor of London, said: "One obvious point, it is completely wrong to blame this killing on Islam."

Senior officers in the Metropolitan Police downplayed the threat of public disorder but said they would be monitoring any potential threat and working with local communities.