Saudis blame al Qaeda for bombs
Saudi officials prevented what would have been a much larger attack.
Gallery: Images of Saudi blast
WASHINGTON (CNN) -- A senior Saudi official has said the Saudi government believes al Qaeda is responsible for the suicide bombings in Riyadh on Wednesday.
The attempt to detonate multiple bombs at once "fits the pattern of an al Qaeda operation," the official said, adding that al Qaeda has threatened Saudis before.
"Who else sends suicide bombers to blow up cars in the midst of urban centers? Who else has publicly said we are going after the Saudi state," the official said.
"Who else has publicly said they are planning to do more of these things? You put it all together and that's the end of it."
The bomb which detonated in the Saudi capital ripped through a five-story building Wednesday and could be heard up to a half-mile away.
The Interior Ministry said four people were killed in the blast and about 150 were injured.
Earlier reports from hospital sources had indicated 10 people were killed, and eyewitnesses said the bomber was blown apart in the explosion.
The bomber attempted to drive an explosive-packed car into the Traffic Department building, which houses police offices, at around 2 p.m. local time, the Saudi Interior Ministry said.
He was stopped by officers about 30 meters from site and outside the old General Security building, where the bomber set off the explosion, the ministry said.
The dead include a civil servant, two security officers and an 11-year-old Syrian girl, Interior Ministry officials announced.
Of the 148 injured, 45 remained hospitalized Wednesday night and three of those were in critical condition, the ministry said.
Television pictures from the scene showed the entire front of the building had been shattered. Burned-out and damaged cars littered the area.
This is the first time terrorists have targeted a Saudi government facility, the official said, adding that foreigners do not frequent the area.
But he pointed out that the planning of the attack "was not as effective as it could have been," citing the fact that several individuals abandoned their vehicles when chased by authorities, and did not have a back-up plan.
The "clumsiness" of the attacks, including the fact that the bombers might have had the wrong target, indicate the operation was undertaken by the "second echelon" of al Qaeda leadership, the official said.
The Saudi government has been on alert for a possible attack for some time, the official said, adding they are "still on high state of alert" for further attacks.
Last week the U.S. State Department ordered most of its personnel in the kingdom and all family members out of the country.
U.S. Deputy Secretary of State Richard Armitage, in Riyadh Wednesday, said, "The terrible bombing here in Riyadh today showed the wisdom of that decision."
Armitage said the United States and Saudi Arabia shared information about the latest threats as part of ongoing cooperation in combating terror.
Saudi Arabia has mounted a massive effort to combat terrorists in the kingdom since deadly attacks last May and November.
A senior Interior Ministry official said that authorities, tipped off that six explosions had been planned, had found and defused five of the bombs.
Truck bombs defused
On Tuesday, Saudi security forces defused two truck bombs outside Riyadh, a security source said, bringing the number of car bombs seized in the kingdom to five within a week.
The vehicles were discovered late Monday at Shuaib Juraidal in Rumhiyah village, 56 miles (90 kilometers) east of Riyadh.
After the two vehicles were found, security forces and helicopters searched the area for armed men, who fled the area in a jeep, residents told Arab News.
On Sunday, an Interior Ministry official announced the arrest of eight suspects linked to recent deadly clashes with security forces and car bombs. (Full story)
The Saudi Press Agency quoted the official giving details of three seized vehicles packed with thousands of pounds of explosives, including one vehicle authorities had been searching for since February.
Saudi police set up several checkpoints in Riyadh.
-- CNN's Caroline Faraj and State Department Producer Elise Labott contributed to this story