Terror cells in Saudi Arabia may have al-Qaeda links

The warning said the US government continued to receive indications of "terrorist threats aimed at American and western interests, including the targeting of transportation and civil aviation".

The warning, which replaces an alert issued in August, said there was "credible information" that western aviation interests in Saudi Arabia had been targeted.

An unnamed Saudi official told the Reuters news agency that the kingdom believed such warnings to be "exaggerated precautions" and that the authorities could guarantee security by preventive means.

The US State Department alert is the latest in a series of recent warnings concerning the threat of terrorism in Saudi Arabia.

The US embassy in Riyadh has already urged the 40,000 Americans in Saudi Arabia to be particularly vigilant in the face of possible attacks during the Muslim holy month of Ramadan.

Crackdown

The British Foreign Office warned on Friday against all but essential travel to the kingdom, prompting a rebuke from the Saudi authorities who said Britain should have consulted them first.

The Saudi ambassador to Britain, Turki al-Faisal, said: "The kingdom wishes that when such advice is given by sources outside the kingdom that there would be co-ordination between the people giving the advice and the authorities in the kingdom."

He said Saudi Arabia had been actively cracking down on terrorist networks since the attacks on foreign workers' compounds in Riyadh in May that killed 35 people including two Britons.

On Thursday, 600 alleged militants with links to al-Qaeda were reported to have been arrested in the kingdom.

BBC security correspondent Frank Gardner says Saudi Arabia has a problem at the moment with terrorist groups, which are well armed.

He added that the plot is thought to be linked to Osama Bin Laden's al-Qaeda network, and that those planning the attacks may well change their plans because of the travel warnings.

However, he said, there was a similar warning a few days before the Riyadh bombings and that did not stop them carrying out the attack.

The Foreign Office advice says anyone visiting Saudi Arabia should keep a low profile and avoid public gatherings.

Travellers have also been told to be vigilant, especially in public places popular with foreigners - such as hotels and shopping malls.