Razaq Raj, who is a senior lecturer at Leeds Metropolitan University, said he knew that Shahzad Tanweer, Hasib Hussain and Mohammad Sidique Khan had been banned but did not know the reason why.
Mr Raj made the comments as he was explaining how mosques and Islamic societies in the city were anything but hotbeds for radicalism and fundamentalist groups.
He said: "I know the three mosques in Beeston had banned them - the ones in Stratford Street, Hardy Street and Tunstall Road. It could be for all sorts of reasons."
The mosques are close to the home of Tanweer, whom police believe blew himself up in the Aldgate blast. The Stratford Street mosque is just two streets away from his Colwyn Road home.
It is also close to a house which has been the centre of intense police activity, and which remains cordoned off from Stratford Street.
Mr Raj's revelations came as further clues emerged about the social centres where the bombers might have met each other. The latest centre to be raided was an Islamic bookstore around the corner from the home of Tanweer, who killed seven in the Aldgate blast.
According to signs outside the shop, the centre provides not only Islamic literature but media services, youth activities, orphan sponsorship, and seminars and presentations. It is only a few hundred yards from the former Hamara community centre, which has also been raided and where a number of the bombers have been seen.
The community centre, in Lodge Lane, is a meeting place for young Muslims, including three brothers whose former home has also been at the centre of police activity and who are being questioned by detectives at Paddington Green police station in London.
It is understood that one of the brothers worked at the Iqra bookshop. One local, who only wished to be known as Arif, said: "The bookshop has absolutely nothing to do with terrorism. It is just a place where people go to meet, have a chat and read books. I don't know why the police had to do this but it will only inflame local people around here."
Forensic officers also removed bags containing computer equipment from the former Hamara centre. Two officers in protective suits and masks carried out six bags clearly containing computer devices from the property in the Beeston area of Leeds.
Police threw a 100m cordon around the centre on Thursday before conducting an examination of it, using robotic devices. Shortly before 10.45am yesterday the metal shutters covering the front of the building were opened and the forensic officers emerged clutching the bags, which were then put in the back of a police van.
Mr Raj, who is also a member of the Leeds Islamic Centre, said he wanted to counter reports that the mosques in Leeds were in any way homes to radicals. His claims bear out the testimony provided by many worshippers at the Stratford Street mosque.
Mr Raj also said that he had strong links with the Islamic societies at both of the universities in the city and had never heard of any fundamentalist influence there. He said: "The last thing we want is radical groups in Leeds."
He added: "I can tell you categorically that at Leeds Metropolitan University and Leeds University there are no radical groups there. If there was a problem, I would report it. I've never had to."
Meanwhile, a statement from the East London Mosque and the Islamic Forum Europe, while saying the country had to stand united and not let extremists divide it, added that the Muslim community alone could not prevent similar atrocities.
The statement said: "Political leaders need to raise their heads out of the sand and find real answers not only on how to deal with incitement to hate but also why British-born and brought-up youths find residence with hate-inciters which leads them to lay down their lives in murdering their fellow citizens."