A homicide bomber driving a van disguised as an ambulance blew up his vehicle Wednesday in front of a hotel frequented by Westerners, witnesses and police said. Iraqi police reported four people were killed, and South Africa said one of its nationals was among them.

The U.S. military initially reported three dead, then said only the driver was killed. A spokesman refused to explain why the figure was lowered.

The blast at the Shaheen Hotel (search) also injured 17 people, according to hospital officials. The spokesman for the South African Foreign Ministry, Ronnie Mamoepa, said one South African was killed and four injured in the blast.

The bombing occurred about 6:40 a.m. after security guards opened fire on the vehicle -- a white van with Red Crescent markings -- as it maneuvered around concrete barriers in the street, witnesses said.

The explosion gouged a huge crater in the street, shattered the ground floor of the three-story hotel and damaged at least three other buildings nearby.

At least 10 cars parked along the street were severely damaged, some reduced to mounds of twisted metal. The blast hurled remains of one car across the street, and other cars were set on fire.

Residents of the hotel include the labor minister, Sami Izara al-Majoun, who was unhurt.

"My guards came to the room and rushed me downstairs. The hotel was burning and there was fire and smoke everywhere," al-Majoun said.

He said some foreigners were staying in the hotel but he didn't know their nationalities or profession.

The hotel is located in the Karadah neighborhood (search), which includes several foreign embassies -- including the Swiss, Polish and Armenian -- and the main station of the security force protecting diplomatic missions.

"If you see my house, you wouldn't be able to recognize it," said Sonya Tatyosian, who lives across the street from the hotel. Still dressed in her pajamas, she stood weeping on the street as she used a friend's satellite phone to call her brother in California.

"I am OK," she sobbed. "Just didn't want you to worry."

It was the first vehicle bombing in Baghdad since Jan. 18, when 31 people were killed in a blast at a main gate to the headquarters of the U.S.-led coalition. Most of the dead were Iraqis.

At least five hotels used by foreigners in Baghdad have been attacked by insurgents in the past with car bombs, rockets and other explosive devices.

The attacks underscore the precarious security situation in Baghdad nine months after the collapse of Saddam Hussein's (search) regime. Wednesday's attack came a day after a United Nations team arrived in Baghdad to determine whether it is safe for the world body to send a mission here to study prospects for an early legislative election.

Shiite Muslim cleric Grand Ayatollah Ali al-Husseini al-Sistani has demanded direct elections for a provisional legislature, which in turn will select a government to take power by July 1. But Washington wants lawmakers chosen in 18 regional caucuses, saying it is too unstable to hold early elections.

U.N. Secretary General Kofi Annan (search) withdrew international staff from Iraq last year after two attacks on the U.N. headquarters in Baghdad -- one of them an August vehicle bombing that killed 22 people, including top U.N. envoy Sergio Vieira de Mello.

Iraqi leaders have urged the United Nations to return to provide legitimacy to the new government.

Wednesday's bombing followed one of the bloodiest days in recent weeks. Ten people -- six U.S. soldiers, two staffers of the international television network CNN and two Iraqi civilians -- were killed Tuesday.

A roadside bombing Tuesday near Iskandariyah, some 25 miles south of Baghdad, killed three American troops, a military statement said. Earlier, a bomb exploded near an 82nd Airborne Division convoy in Khaldiyah, west of Baghdad, killing three paratroopers and critically wounding one. Two Iraqis were also killed.

South of the capital, a driver and a translator-producer working for CNN were shot and killed Tuesday while returning from an assignment, the network said. It said a cameraman was injured. Both the dead were Iraqis.