Updated

A homicide attacker bombed a security police building in the Saudi capital Wednesday, killing at least four people and wounding 148. The attack had the hallmark of an Al Qaeda operation, officials said.

The explosion, heard three miles away, shattered the glass facades of nearby buildings and ignited several fires. Smoke billowed from the seven-story General Security building, where workers issue drivers license renewals and do other administrative tasks.

The deathtoll was expected to rise after hospital officials reported early Thursday that body parts have been recovered possibly indicating four more deaths, in addition to the four already confirmed by the Interior Ministry.

The bombing came about 2 p.m., a time when staff would have been leaving their offices. The headquarters of the Saudi Security Forces (search) used to be in the building. Some security forces still work in part of the building, a Saudi official said, speaking on condition of anonymity.

A woman who lives nearby, Hanan Batteesha, said that after the explosion, "We heard wails and cries, then saw our neighbors running down the stairs." She rushed out with her two children.

"The fronts of the buildings around us were damaged. The air conditioners were mangled, and there was smoke everywhere," she said.

The Interior Ministry said the assailant tried to drive his vehicle into the General Security building.

When stopped by guards, the driver exploded the car about 100 feet from the gate, the government said.

Five other vehicles were apprehended with explosives, the Saudi official said.

No Americans were hurt in the bombing, said U.S. Embassy spokeswoman Carol Kalin. Half an hour after the attack, Deputy U.S. Secretary of State Richard Armitage (search) met with Foreign Minister Saud al-Faisal (search) at the Foreign Ministry.

Crown Prince Abdullah (search) and Interior Minister Prince Nayef (search) visited the wounded in the hospital.

"I am sorry that those criminals are Muslims," Nayef told reporters. He said Saudis should not cooperate or sympathize with militants "because those who do will be considered criminals."

"The terrorists are not targeting foreigners; they are targeting the nation," Nayef said.

The General Security service has been heavily involved in the campaign against Islamic militants that followed the homicide attacks in May and November 2003 in Riyadh.

Those attacks, also vehicle bombs, killed 51 people including the assailants. They were blamed on Al Qaeda, which carried out the Sept. 11 attacks on the United States.

A U.S. counterterrorism official, speaking on condition of anonymity, said the attack has the hallmark of Usama bin Laden's Al Qaeda network and appears to be related to the terrorist group. Al Qaeda, the official noted, has previously used car bombs in Riyadh.

The Saudi official agreed that Wednesday's attack fit Al Qaeda's pattern.

Saudi U.S. ambassador Prince Bandar bin Sultan said in Washington that the attack was aimed at "the Saudi people and the royal family and officials of the government ... are all Saudi citizens," said Bandar.

Bandar, who spoke after meeting with national security adviser Condoleezza Rice, pledged his nation would "fight them [terrorists] hard, there will be no compromise."

The attack came days after the United States ordered the departure of nonessential U.S. government employees and family members from Saudi Arabia. The U.S. Embassy in Riyadh issued an advisory warning of "credible indications of terrorist threats aimed at American and Western interests in Saudi Arabia."

Last month, an Internet message purportedly from Al Qaeda threatened Saudi security officers, saying that to attack them "in their homes, or workplace, is a very easy matter."

Saudi police said last weekend that they seized three booby-trapped Sport Utility Vehicles loaded with more than four tons of explosives. The vehicles had apparently been abandoned by militants involved in a shootout with security forces.

There were conflicting accounts on the death toll throughout the day.

The Interior Ministry said four were killed: two police officers, an adult and an 11-year-old Syrian girl. But the ministry's statement did not include the homicide bomber, whose death was reported to The Associated Press by a security official speaking on condition of anonymity.

Officials from the three hospitals that admitted casualties said at least nine people were killed.

The Interior Ministry said 148 people were wounded, three critically, according to the official Saudi Press Agency. Forty-five remained hospitalized.

The casualty tolls could rise as rescue workers were still going through the rubble late Wednesday. Most of the casualties at King Faisal Specialist Hospital (search) were police, but there were also four children, said hospital spokesman Fahd al-Shaar.