Saudi Arabia has denied that a car bomb which killed a German citizen in the capital, Riyadh, on Sunday was a terrorist act.

The kingdom's intelligence chief, Prince Nawwaf, blamed the attack on "illegal traders" and insisted that Saudi Arabia's foreign community was safe from terror attacks.

The incident was extraordinary and isolated

Prince Nawwaf Saudi intelligence chief

Sunday's car bomb attack is the latest in a series targeting Westerners in Riyadh in recent years.

Correspondents say Western diplomats believe the attacks are the work of Muslim extremists.

The Saudi authorities have blamed previous attacks on disputes among expatriate workers involved in smuggling alcohol.

Seven Westerners, including five Britons, are awaiting trial for bomb attacks in 2000 and 2001 and could face the death penalty if convicted.

String of attacks

Prince Nawwaf said in a statement released on Monday that Sunday's attack was "extraordinary and isolated and... the result of a struggle and disputes among traders in illegal matters".

The victim was a 56-year-old German employed by an electronics company in Saudi Arabia.

Previous bombings

June 2002 - Briton Simon Veness killed in car bomb attack May 2001 - An American is seriously injured by a bomb in Khobar March 2001 - A Briton and an Egyptian are injured by a bomb outside a Riyadh book shop December 2000 - A Scottish man is injured by a blast in Khobar November 2000 - Two bombs in Riyadh kill a British man and injure four other Britons

The explosion occurred on Abdulhamida-Khateb street in the north of the city, just 100 metres from a car bombing which killed a British national two years ago.

Christopher Rodway, 47, died when his car was blown up by what police said appeared to be a booby trap.

Most recently another Briton - Simon Veness - was blown up in June this year, provoking fears that Westerners were being targeted in the aftermath of the 11 September attacks on the US.

Several Western embassies in the kingdom have advised their nationals to remain vigilant and to ensure the security of their vehicles.

One Western diplomat who spoke to the French news agency AFP on condition of anonymity said he found Prince Nawwaf's remark that the latest attack was isolated "somewhat unusual".

"There has been no result on previous incidents which targeted Westerners although they happened long ago...

"Westerners here are certainly concerned. You are bound to be concerned when you have nothing about the [previous] incidents and the perpetrators."