Ten days after Islamic radicals carried out deadly attacks on the London transport system, Britain's largest Sunni Muslim group on Sunday issued a binding religious edict, a fatwa, condemning the July 7 homicide bombings as the work of a "perverted ideology."

The Sunni Council (search) denounced the bombings as anti-Islamic and said the Koran, the Muslim holy book, forbade suicide attacks.

"Who has given anyone the right to kill others? It is a sin. Anyone who commits suicide will be sent to Hell," said Mufti Muhammad Gul Rehman Qadri (search), the council chairman. "What happened in London can be seen as a sacrilege. It is a sin to take your life or the life of others."

The council said Muslims should not use "atrocities being committed in Palestine and Iraq" to justify attacks such as those in London that killed 55 when homicide bombers struck in three Underground trains and a double-decker bus, the fatwa declared.

"We equally condemn those who may have been behind the masterminding of these acts, those who incited these youths in order to further their own perverted ideology," Qadri said.

More than 2,000 Sunni clerics, scholars and community leaders attended Sunday's meeting, which was scheduled before the bombings.

Also Sunday, government officials dismissed claims that lax attitudes allowed homegrown homicide bombers to develop. The Sunday Times reported that one suspected bomber, 30-year-old Mohammad Sidique Khan, was investigated last year by MI5, Britain's domestic intelligence service, but was not regarded as a threat to national security or subsequently put under surveillance.

MI5 began evaluating Khan, a Briton of Pakistani ancestry, during an inquiry that focused on an alleged plot to explode a large truck bomb outside a target in London thought to be a nightclub in Soho, the newspaper said. The private inquiry reportedly evaluated hundreds of potential suspects.

The Metropolitan Police and a spokesman for Prime Minister Tony Blair declined comment.

The bombings have prompted the government to propose new legislation outlawing "indirect incitement" of terrorism — including public praise for those who carry out attacks.

Nevertheless, Charles Falconer, the Secretary for Constitutional Affairs and Lord Chancellor, denied that the government had not been diligent in screening political refugees from Muslim countries, making Britain a fertile recruiting ground for Islamic terrorism.

"In terms of asylum, our policy is: If you are in fear of persecution, you are entitled to come here," the minister said on BBC television. "Obviously, if you then seek to attack the very state that you come to, that gives rise to different questions.

"But I don't think we have been ultraliberal. ... What we have got to do now is unify all the forces in our society, in particular in the Muslim community, against those people who are fundamentally at odds with our values."

The fatwa was issued as investigators in the northern city of Leeds continued to focus on an Islamic bookshop and a house near the home of one of the four alleged bombers, 22-year-old Shahzad Tanweer.

Tanweer, born in Britain to Pakistani parents, was believed to be one of the Underground train bombers and reportedly visited two religious schools on a trip to Pakistan.

Pakistani intelligence agents have questioned students, teachers and administrators at the school in central Lahore, and at least two other Al Qaeda-linked radical Islamic centers, showing pictures and a dossier on Tanweer.

In an interview with an American cable channel, British Defense Secretary John Reid expressed concern about Pakistan's religious schools, saying the madrassas "are a major source of international instability and contribute largely toward the growth of terrorist activity."

Police said Sunday night that six men were arrested in Leeds under Britain's anti-terrorism act, but later retracted the claim and said they were arrested on immigration offenses. There is no connection between the July 7 London bombings and the arrests Sunday night, police said.

"There was a mistake earlier in that entry ," a spokesman said, speaking on condition of anonymity according to government policy.

Tanweer, Khan and 18-year-old Hasib Hussain, who were all from the Leeds area. Hussain was also a Briton whose parents were from Pakistan. The fourth suspect, Jamaican-born Germaine Lindsay, 19, who came to Britain as an infant, lived in Luton, a city north of London.

Police on Saturday released an image captured by surveillance cameras showing all four bombers with backpacks entering the Luton train station on the morning of the attacks.

Investigators say the four took a train from Luton to London's King's Cross station, where they split up to carry out the bombings.

Officers have also been searching the Leeds home of an Egyptian biochemist for more evidence after investigators reportedly found traces of explosives in the man's bathtub. Magdy Mahmoud Mustafa el-Nashar is being interrogated by Egyptian authorities, who say the biochemist denies having any connection to the attacks. He was arrested at the Cairo airport in the days after the bombing.

Egypt is not prepared to hand el-Nashar over to Britain, Egyptian security officials said. British investigators are in Cairo to take observe the questioning. The two countries have no extradition treaty.