Two men suspected in taking part in the July 7 attacks arrested

The report said the degree of al-Qaida involvement in the July 7 attacks, if any, was unclear, and it had found no links between the attacks and those who mounted failed bombing attempts against the London transit system two weeks later, according to the ABC News.

Photo: Two men suspected in taking part in the July 7 attacks arrested

Security services had come across two men who went on to carry out last year's July 7 suicide bomb attacks on London but did not believe they posed an urgent threat, a parliamentary report said on Thursday.

Mohammad Sidique Khan and Shehzad Tanweer were among four British Islamist militants who set off rucksack bombs on three underground trains and a double-decker bus, killing 52 people and wounding more than 700, Reuters reports.

The parliamentary panel investigating the bombings - the first suicide attacks in Western Europe - said it was not clear if they had any direct link to al Qaeda. The committee's chairman said he suspected the plot had been hatched in Britain.

The intelligence and security committee did not blame officials for not pursuing Khan and Tanweer, who featured on the margins of another terrorism probe, saying there was no indication at that time they were significant.