Letter from Bin Laden found on body of Saudi bomber

A letter from Osama bin Laden and a telephone call made from Iran by his son Saad are linked to a series of al-Qa'ida attacks on Westerners in Saudi Arabia, according to Western diplomats and Saudi intelligence officials.

The letter from al-Qa'ida's leader was found on the body of Yosif Salih Fahd Alayeeri, one of 19 attackers involved in a closely co-ordinated series of bombings in Riyadh on 12 May, who was killed in a shootout with security forces in central Saudi Arabia in May. The Saudi authorities have refused to divulge the contents of the letter, confirming only that it was found on the dead terrorist.

Two days before the bombings, which killed 34 people, including nine Americans and two Britons, Saad bin Laden made a telephone call from somewhere in Iran to another member of the same al-Qa'ida gang, according to a senior Western diplomat. The unidentified Saudi suspect was arrested as part of a crackdown on Islamist militants after the May bombings. Authorities said he had revealed the details of the telephone conversation between himself and Saad bin Laden under interrogation.

British Airwayshalted flights to the kingdom on Wednesday last week after Saudi authorities learnt of a plot to shoot down one of its planes with a missile. The plan is believed to have been the work of the same wide network, directed by Bin Laden and associates, including his son Saad, to which the Riyadh gang belonged. Intelligence about the plot probably came from CIA agents working in the kingdom, and with whom the Saudis are now sharing information on al-Qa'ida.

The attack was foiled when a Saudi police special forces ambushed 10 terrorist suspects who had escaped a shootout in Riyadh the night before. Three Saudi officers died and five suspects were captured.

Details of the planned missile attack were found in documents in a car used by the gang, and BA announced it was suspending flights to Saudi Arabia the next day.

Adel al-Jubeir, a Saudi foreign policy adviser, partly confirmed the details in an interview yesterday with CNN. "One of the cells that was broken up ... there were maps, there were certain things that indicated that there was a high level of interest in British Airways," Mr Jubeir said. "The conclusion that was arrived at by British Airways ... was that there may be a threat there."

There have been fears of a missile attack against a civilian airliner in Saudi Arabia since May last year, when a shoulder-launched SA-7 missile was fired at an American fighter plane taking off from the Prince Sultan air base. Earlier, explosives were found outside the base, with another al-Qa'ida letter attached, demanding that all American forces withdraw.

Much of the intelligence coming out of Saudi Arabia is emerging from CIA interrogations. This is given more credibility by international experts than details provided by the Saudi Interior Ministry. Some of the best information is believed to be from Ali Abdul Rahman al-Faqaasi al-Ghamdi, who is accused of masterminding the Riyadh attacks, and who surrendered in Jeddah. Mr Ghamdi met Bin Laden insouthern Afghanistan before the Taliban regime fell.

It has not been revealed whether Mr Ghamdi was the source of the information about Saad bin Laden's phone call, but the revelation has severely affected relations between Riyadh and Tehran. The Iranians have denied US claims that the Riyadh bombings were directed from their territory.

Iran has declined to reveal the identities of terrorist suspects it is holding, other than saying they include "important and less important members" of al-Qa'ida. But US officials and Arab press reports say Saad bin Laden, who has been stripped of Saudi citizenship, is among those being held.

The Saudi Interior Minister, Prince Nayef, has confirmed that all the gangs arrested in the country since 12 May have links to al-Qa'ida.