Two homicide bombers detonated car bombs Sunday outside the closely guarded Baghdad Hotel (search) that serves as home to officials associated with the U.S. occupation, killing a guard and five bystanders.

The Pentagon said gunfire from Iraqi guards and U.S. personnel aborted the drivers' plan to hit the hotel, also reportedly home to some members of Iraq's interim Governing Council (search).

At least one guard was reported among the dead; the two bombers also were presumed killed. One member of the 25-seat Governing Council, Mouwafak al-Rabii (search), told Al-Jazeera satellite television he suffered a slight hand injury.

It was the seventh fatal vehicle bombing in Iraq (search) since early August, attacks that have taken more than 140 lives. All have targeted institutions perceived as cooperating with the U.S. occupation of Iraq, and none has been reported solved.

The lunchtime attack sent terror-stricken Iraqis fleeing up Saadoun Avenue, over broken window glass from banks, restaurants and shops and past the bloodied bodies of injured. American helicopters and combat vehicles converged on the chaotic scene as black smoke from burning cars billowed over the central city.

The six victims and 32 injured reported at al-Kindi Hospital -- four in critical condition -- were all Iraqis, authorities said. The U.S. military said three Americans were slightly injured.

"We will work with the Iraqi police to find those responsible and bring them to justice," Iraq's U.S. civilian administrator, L. Paul Bremer, said after Sunday's bombing.

But along Saadoun Avenue, feelings ran high against the Americans and their inability to stop the bombings. "Hey! Hey! This regime's a failure!" a group chanted in Arabic at a group of U.S. soldiers as the fires raged.

Elsewhere in Iraq, other attacks on Americans continued Sunday. Two U.S. soldiers -- military police -- were slightly injured in a blast, apparently from a roadside bomb, just outside the main U.S. Army base in Tikrit, 120 miles north of Baghdad. Another soldier was wounded when his convoy came under small-arms and grenade attack 60 miles south of the northern city of Kirkuk.

In other developments:

-- Hundreds of thousands of Shiite Muslim pilgrims concluded a weekend of religious celebration in the holy city of Karbala, south of Baghdad. The festival was peaceful despite a fiery Friday sermon by hard-line cleric Muqtada al-Sadr, who railed against the U.S. occupation and announced formation of his own Islamic "government."

-- Members of a visiting U.S. congressional delegation expressed American determination to stick it out in Iraq. "We are here to stay until these people are ready to take over," said Rep. H. James Saxton, R-N.J., referring to members of Iraqi security forces with whom the delegation met.

-- A man claiming to speak for an Iraqi resistance group warned in a compact disc recording against foreign troops joining U.S.-led occupation forces, saying they will be treated as occupiers and provoke attacks on their home countries.

A statement signed by the same unknown group, "The Jihad Brigades of Imam Ali bin Abi-Taleb," promised to kill every member of the Governing Council and Iraqis who cooperate with the occupation. It was impossible to verify the authenticity of the statement or the recording.

The heavily guarded Baghdad Hotel sits at the foot of a short side street running from Saadoun Avenue. A tall wall of concrete slabs guards the intersection where the street meets the avenue. Bremer's Coalition Provisional Authority said some of its staff and contractors reside in the hotel, and for weeks it was rumored to be home to CIA staff, although the U.S. intelligence agency denied Sunday it was their headquarters.

Witnesses said two cars sped toward the intersection, one going up the wrong lane on Saadoun, a two-way road, and suddenly veered behind the barrier to head toward the hotel.

Sabah Ghulam, 37, said one of the cars came at him as he rode in an automobile past the barrier. "The car was in front of us, a 1990 Toyota Corolla," he said. "He suddenly turned in toward the hotel. ... A policeman shot at him four times, and then there was the explosion."

In Washington, Pentagon spokeswoman Lt. Col. Cynthia Scott-Johnson said both vehicles were fired on by Iraqi guards and by Americans.

"Both vehicles then detonated, wounded three U.S. personnel slightly," she said. She didn't specify whether the U.S. personnel were military or civilian; at least one civilian gunman who looked American was seen at the scene.

Lt. Col. George Krivo, a military spokesman in Baghdad, said two cars came at a high speed toward the checkpoints but it was unclear if both contained explosives.

Ghulam described the one driver as light-skinned, clean-shaven and wearing a hat. He didn't look like an Iraqi, he said. Ghulam's vehicle, passing the 15-foot-tall barriers when the cars exploded on the other side, suffered only shattered windows.

The U.S. Army's Col. Peter Mansoor, of the 1st Armored Division, said of the barriers, "They prevented a greater loss of life. So the security worked."

The force of the 12:45 p.m. blasts blew down a half-dozen sections of the concrete wall, shattered brick walls up to the third floor above the site, and blew out windows up to three blocks away.

"Our office is on the fourth floor. The windows blew in. Some of the girls fainted," said a dust-smudged Salima Saddam, 33, as she was evacuated. The first of the injured were rushed away in police cars.

Mansoor said no one was seriously injured at the hotel.

Saad Hamid, 41, owner of a shop near the scene, said police had caught a would-be car bomber at the same spot six weeks ago before he could detonate his explosives. Authorities then erected the blast wall at the end of the street.

The Associated Press contributed to this report.