Officials in the British capital raised the death toll to 55, and police in the northern city of Leeds searched an Islamic shop, the home of an Egyptian biochemist and another address for more evidence after investigators reportedly found traces of explosives in the man's bathtub.
The hunt for clues pointing to those who recruited, financed and supplied the four bombers, who blew themselves up on three underground trains and a double-decker bus on 7 July, focused on the men's ties to Pakistan.
Authorities in Islamabad said on Saturday that they questioned students, teachers and administrators at one of two religious schools said to have been visited by one of the suspects.
Asad Farooq, a spokesman for the school, told The Associated Press that intelligence agents had been around on Saturday but denied that the suspect, Shahzad Tanweer, had ever been at the school.
El-Nashar has denied any link to
the attacks in London
British investigators say Tanweer, 22, carried out the bombing of the London Underground's Aldgate station.
Senior Pakistani intelligence officials said authorities were examining a possible connection between Tanweer and two al-Qaida-linked militant groups.
Death toll rises
The US television network ABC reported on Saturday that the FBI was looking into possible ties between unidentified people in New Jersey and a Jamaican-born Briton whose name has been given as both Lindsey Germaine and Lindsay Jamal.
The man has been linked to the worst of the suicide attacks - a subway bomb that killed at least 26 people between the King's Cross and Russell Square stations.
Authorities raised the confirmed death toll from 54 to 55 after an injured victim died overnight at a hospital. About 700 people were injured in the morning rush-hour attacks, and police said more than 40 people remained hospitalized, at least six of them in critical condition.
The death toll in the bombings
continues to rise
In a speech in central London on Saturday, Blair said authorities were facing an "evil ideology" in their struggle against extremism.
"The greatest danger is that we fail to face up to the nature of the threat that we're dealing with," he said.
"And what we are confronting here is an evil ideology. ... It is a battle of ideas, of hearts and of minds, both within Islam and outside it."
British police on Saturday released a security camera image showing the four suspected London bombers together at Luton station north of the capital, on the morning of the attacks last week.
Police began searching a property in Leeds, a few streets away from Tanweer's home, on Saturday afternoon, posting guards outside the entrance and erecting scaffolding for sheets to shield the site from media and onlookers, Britain's Press Association reported. West Yorkshire police would not immediately confirm the report.
Investigators also continued searching a shop called Iqra Learning Centre in the Leeds neighborhood of Beeston. The shop appeared to sell Islamic books and DVDs and offer seminars and presentations.
Two investigators, wearing white protective suits, could be seen inside the store before officers covered the windows with gray plastic sheeting. The immediate area remained cordoned off.
Police have raided several
shops and houses in Leeds
The shop is about six kilometers from Egyptian biochemist Magdy Mahmoud Mustafa el-Nashar's townhouse, where British media reported that police found evidence of the explosive TATP inside a bathtub.
Police continued searching the house on Saturday from behind large black and white sheets.
TATP was used by shoe bomber Richard Reid, whose attempt to blow up a trans-Atlantic flight from Paris to Miami in December 2001 was thwarted. Reid pleaded guilty to US charges and is serving life in prison.
Egypt's Interior Ministry said Egyptian authorities were interrogating el-Nashar, 33, who had studied for one semester at North Carolina State University and the University of Leeds. It said el-Nashar denied any connection to the attacks.
Egypt is not prepared to hand el-Nashar over to Britain, Egyptian security officials said on Saturday as British investigators arrived to question him. The two countries have no extradition treaty.
British media reported that bombing suspect Mohammed Sidique Khan, 30, visited the Houses of Parliament last year as the guest of Labour Party lawmaker Jon Trickett. It said Trickett alerted security officials when he realized Khan, who had worked as a counselor at a school in Leeds, was one of the bombers.
"We are devastated that our son may have been brainwashed into carrying out such an atrocity"
Family of Mohammed Sidique Khan
West Yorkshire police released a statement from Khan's family on Saturday saying he must have been "brainwashed" and calling on people to "expose the terror networks which target and groom our sons to carry out such evils".
"We are devastated that our son may have been brainwashed
into carrying out such an atrocity, since we know him as a
kind and caring member of our family," the family said.
Samantha Lewthwaite, the wife of the Jamaican suspect, told The Sun tabloid newspaper that she refused to believe he was among the bombers "until they have his DNA".
"He wasn't the sort of person who'd do this. I won't believe it until I see proof," she said.
The newspaper said Lewthwaite was pregnant with the couple's second child and was under police protection.
In a statement issued Friday, the family of Hasid Hussain - the 18-year-old believed to have blown up the double-decker bus, killing himself and 13 others - said it was unaware of his activities.
"We would have done everything in our power to stop
him," it said.