Some of Britain's mosques are adding extra security in the wake of the deadly Norway attacks, Muslim community leaders said Sunday.

In recent weeks, a pig's head was left at a mosque outside of Oxford, while there have been repeated attacks on women wearing headscarves and full-face coverings, said Mohammed Shafiq of the Ramadhan Foundation, one of Britain's largest Muslim organizations.

Muslim groups say they have long warned Britain's police of increasing hostility from far-right groups.

"People are looking over their shoulders and afraid that we will be the next target," Safiq told The Associated Press in a telephone interview from the sidelines of an international gathering of Muslim scholars and leaders Sunday. "As a result, we've told people to be extra vigilant and there will be added security placed at mosques."

An online manifesto ranting against Muslim immigration to Europe was written by the alleged assailant, 32-year-old Norwegian Anders Behring Breivik, and he had been working on it for years, said his lawyer, Geir Lippestad.

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On Friday, seven people died in a bombing outside government headquarters in Oslo, Norway. Hours later, 86 more died in a shooting spree on a nearby island.

Shafiq said security discussions were under way with police in Manchester, home to many of Britain's nearly 2 million Muslims. Thousands will be gathering at mosques this week ahead of Ramadan, the Muslim fasting month that begins at the end of the month. Manchester police would not immediately confirm the talks.

Britain's Muslims have seen an increase in attacks since 2005, when homegrown suicide bombers killed 52 people during morning rush-hour attacks in London.

Since the suicide bombings, and in the wake of the Sept. 11 terror attacks in the United States, more resources have been dedicated to fighting Islamic terrorism instead of far right or leftist extremism. As a result, Britain's police have been left to track activity while Britain's domestic spy agency of MI5 has focused on serious national security threats.

"We take the threat of domestic extremism very seriously," a spokesman for Scotland Yard said on condition of anonymity because he was not authorized to speak about police operations. "The U.K. police force gathers intelligence and information on a number of groups, but we do not discuss individual groups."

The European police agency has said it will set up a task force to assess the threat of far right and leftist groups in Scandinavian countries. Europol spokesman Soeren Pedersen said Sunday the group could be expanded to include members from other countries such as Britain.

Far-right political groups have gained some ground in recent years in Britain and other parts of Europe.

The all-white British National Party, for example, won its first ever seat in recent European parliamentary elections.

The party, which does not accept nonwhite members and calls for the "voluntary repatriation" of immigrants, won two of Britain's 72 seats in the European Parliament, gaining ground in economically battered areas that once were strongholds of Britain's left-wing Labour Party.

The win was a breakthrough for the party and its Cambridge University-educated leader Nick Griffin, who once called the Holocaust a hoax.

Last year, Griffin's appearance on a flagship television debate show proved to be a huge ratings boost for the BBC -- some 8 million people tuned in to watch Griffin criticize Islam as a wicked faith, express his disgust at homosexuals and defend the Ku Klux Klan.

The English Defense League, meanwhile, released a statement Sunday distancing itself from Breivik. The group opposes what it calls the spread of Islam.

"Terrorism and extremism of any kind is never acceptable and we pride ourselves on opposing these," the statement said. "We strongly oppose extremism and always reject any suggestion of us being either extremists or far-right, due to our great past record of dealing with anyone who holds such extremist views."

Stephen Lennon, the group's founder, was charged earlier this year with assault following an incident at one of the far-right group's demonstrations.

Lennon could not immediately be reached for comment on Sunday.

"We've always warned British authorities that they should not just focus on extremists from Muslim communities and that they also needed to tackle far-right extremists," Shafiq said. "It's because of this failure that far right groups have gained ground."

Two European security officials who spoke on condition of anonymity because they were not authorized to speak about the investigation, said they were investigating claims that Breivik and other far-right individuals attended a meeting in London in 2002.

They would not, however, immediately confirm that Breivik had appeared on their radar as a potential threat.

"Extremism and intolerance -- regardless of whether it comes from far-right nationalists or far-right Islamists -- is a threat to us all," said James Brandon, a researcher at the London-based Quilliam Foundation, a group founded by two former jihadists and now dedicated to stamping out extremism.