Two senior al-Qaeda activists in Saudi Arabia made money transfers and used coded text messages to communicate with suspectss in Britain before last month's attacks in London, according to officials, who were quoted by the Telegraph newspaper.
The two men, of Moroccan descent, have since been shot dead. Younis Mohammed Ibrahim al-Hayari, allegedly al-Qaeda's leader in Saudi Arabia, was killed in Riyadh three weeks ago and Abdel Karim al-Mejati died in a shoot-out in the central al-Qassim region in April.
The Sunday Telegraph revealed last week that Scotland Yard was investigating evidence that the two waves of terrorist attacks in London were also planned in Saudi Arabia.
Another newspaper said Saudi officials warned British authorities well ahead of the attacks. The Observer newspaper quoted a security official in the Saudi capital Riyadh as saying that information was passed to MI5 and MI6, Britain's domestic and foreign intelligence agencies respectively.