Police chiefs say community relations in the UK are "reassuringly calm" in the wake of the London bombings, although several forces have reported attacks on mosques.
A fire at a mosque in Leeds was investigated by police
The Association of Chief Police Officers (Acpo) is encouraging people to report any incidents of abuse.
The Muslim community is feeling increasingly vulnerable and concerned, a monitoring team from the association found.
But it also claimed there had been no upsurge in violence and abuse directed at minority groups.
Acpo President Chris Fox said there would have been other low-level, unreported incidents that should be reported so they could be full investigated by police.
He added: "But we are encouraged by the overall calm community response, locally and
nationally, to these terrible events."
Government ministers have said the attacks bore the hallmarks of al-Qaeda, and a claim for the attacks has been made in the name of al-Qaeda by a group calling itself the Abu Hafs al-Masri brigade.
But the BBC's security correspondent Gordon Corera has urged caution over the credibility of the claim.
The London bombings have been widely condemned by UK's the Muslim community.
On Sunday, senior faith leaders jointly issued a strong condemnation of the attacks.
Chair of the Council of Mosques and Imams Sheikh Dr Zak Badawi said: "People do things in the name of Islam which are totally contrary to Islam."
However, since attacks on London, incidents reported by individual police forces have included arson attacks on mosques in Leeds, Birkenhead in Merseyside and Telford in Shropshire.
Acpo said these attacks had caused "little damage".
The Muslim News has reported three further attacks on mosques, one in east London and two in Bristol, and the Muslim Council of Britain has reported several attacks on mosques in north west London.
Sir Iqbal Sacranie, head of the group, said the MCB had been sent a lot of hate mail since Thursday, but had also received a lot of support.
Mr Fox said the police presence in some areas would be boosted to reassure all communities they were being protected.
He said he was "cautiously optimistic" that common sense and "people's best instincts" would prevail.
"It is therefore absolutely crucial that there should no reaction against any
section of the community," he said.
"That would simply play into the hands of the