The swift response to the bombings, as detailed in an official account early yesterday, was reminiscent of the killing last June of the local leader of the al-Qaeda terror network and three associates in the Saudi capital shortly after they posted website photos of the beheading of a US hostage.

An interior ministry statement portrayed at least one of the two bombings as a suicide attack and said there were so far no reports of fatalities among security men or civilians, although several were wounded in the two blasts.

"Before 9:00 pm (1800 GMT) Wednesday, members of the deviant group (the official term for suspected Al-Qaeda militants) blew up a car loaded with a large amount of explosives outside the interior ministry building in Riyadh," the statement said.

Five ministry guards were lightly wounded and a sixth sustained moderate injuries. A number of people who were present at the scene were also wounded and hospitalized, the ministry said without giving an exact figure.

"At the same time, (another) car laden with explosives drove to the special security forces base in east Riyadh ... but security forces were able to intercept it before it arrived to the building. Whoever was inside (the vehicle) detonated it at a distance of more than 350 meters (yards) from the entrance," the statement said.

It said 12 people inside the building sustained slight injuries from flying glass, "and a number of citizens and (foreign) residents who were on the scene" were also wounded.

The ministry did not reveal the identities of the slain militants, but the sequence of events was similar to those of June 18 when security forces gunned down al-Qaeda's local chief Abdul Aziz al-Muqrin and three comrades.

Oil prices surged on news of the latest attacks in the Gulf state, which is the number one oil exporter and sits atop the world's largest crude reserves.

Interior ministry spokesman Mansur al-Turki told AFP several people, mostly civilians, were injured in what was "apparently a suicide operation," adding that "human remains were found in the car which exploded."

Meanwhile AFP from Riyadh reported quoting a newspaper that a Pakistani taxi driver and a Saudi security man were killed in car bombings in the Saudi capital late Wednesday that left another 90 people wounded. , a newspaper reported Thursday.

Al-Eqtissadiyah said the two were killed in an attack against the interior ministry in the centre of Riyadh, as militants struck at the heart of the security forces battling a wave of deadly violence by Al-Qaeda linked suspects.

Suspected Al-Qaeda fighters have killed more than 100 people and wounded hundreds more in Saudi Arabia since launching their attacks, many of which have targeted foreigners, in May 2003.