Riyadh (AsiaNews/Agencies) - Islamic extremists set off bombs and battled with police in the Saudi capital Wednesday night, leaving nine militants and one bystander dead and causing oil prices to jump as the insurgents signalled they will keep up attacks despite the kingdom's crackdown on al-Qaeda.

A car bomb was detonated by remote control near the Interior Ministry in central Riyadh - killing a bystander - followed soon after by an explosion when two suicide attackers tried to bomb a troop recruitment centre, but they came under fire from police and set off their explosives prematurely. The two bombers died, but there were no other reports of casualties.

The attacks came two weeks after al-Qaeda leader Osama bin Laden called on his followers to focus attacks on his homeland and the kingdom's oil installations to weaken both the West and the Saudi royal family.

While damage to the Interior Ministry was minor, it was a bold assault on the government body of Saudi Arabia by Islamic extremists. Prince Ahmed bin Abdel Aziz, the deputy interior minister, told Saudi TV the attackers were all Saudis.

The violence sparked a jump in oil prices in afternoon trading in New York, helping push the price of a barrel of light crude up nearly $2 a barrel to $43.64.

The extremists' biggest attack recently came Dec. 6, when militants said to belong to al-Qaeda's Saudi branch stormed the U.S. consulate in Jiddah, killing nine people.