Four women were among six U.S. military personnel killed after a car bomber slammed into a U.S. convoy in Fallujah, Pentagon sources told FOX News Friday.

The attack, which happened late Thursday night, targeted troops assigned to the II Marine Expeditionary Force (search), the military said. Another 13 Marines were wounded in the attack, spokesman Bryan Whitman.

The Marines said the blast has made it difficult to identify some of the victims.

Three of the female victims were the first women in the Marine Corps to die since the Iraq war began, while the fourth was the first woman in the Navy to die in the conflict.

The terrorist group Al Qaeda in Iraq (search), headed by Abu Musab al-Zarqawi (search), claimed responsibility for the attack, saying six "crusaders" were killed and two Humvees were destroyed. The claim was posted on an Internet site, but its authenticity could not be verified.

Fallujah, the volatile Anbar province (search) town 40 miles west of Baghdad, was the scene of a large-scale campaign in November by U.S. troops to rout militants.

U.S. forces in Fallujah arrested Associated Press Television News cameraman Amer Ali who went to the scene at midday Friday, and his video showed black scorch marks along a road and scattered chunks of metal. Video he shot Thursday showed thick plumes of black smoke rising from the blast.

Meanwhile, an Iraqi reporter working for an American news organization was shot and killed Friday in Baghdad by U.S. troops after he apparently did not respond to a shouted signal from a military convoy, witnesses said. The military had no comment.

The violence comes at a time when the Bush administration is coming under increasing pressure to change strategies in Iraq.

President Bush met Iraqi Prime Minister Ibrahim al-Jaafari (search) at the White House, and both pledged eventual victory over insurgents.

"The enemy's goal is to drive us out of Iraq before the Iraqis have established a secure democratic government. They will not succeed," Bush said at a news conference.

"This is not the time to fall back," al-Jaafari concurred at a joint news conference at the White House.

In an Oval Office meeting, both leaders met to underscore work being done to train Iraqi security forces — a precursor to bringing U.S. troops home — as well as discuss efforts to draft a constitution and rebuild a nation still wracked by a violent insurgency more than two years after the ouster of Saddam Hussein.

On Friday, three separate roadside bombs exploded near U.S. military convoys and a police patrol, officials said.

At least 1,730 members of the U.S. military have died since the war began in March 2003, according to an Associated Press count.

A roadside bomb wounded three Iraqi policemen in Kirkuk, police Maj. Gen. Anwar Mohammed Amin said. The oil-rich city is 80 miles north of Baghdad.

Another bomb went off as a U.S. military convoy was passing on Canal highway near Baghdad's Sadr City (search), police Lt. Col. Kadhim Hamza Abbas said. U.S. forces sealed off the road, Abbas said. No casualties were reported.

A third bomb detonated in southern Baghdad but missed a passing U.S. military convoy, army 1st Lt. Haidr al-Mawla said.

Also, a U.S. military unit hit a roadside bomb Friday in southern Baghdad, said Army Sgt. David Abrams, a spokesman for Task Force Baghdad. No casualties were reported.

In other violence, a mortar attack on a Mosul police academy missed its target Friday and struck nearby homes, killing one Iraqi woman, police Capt. Ziyad Ahmed and Dr. Asaad Khalid said. Mosul is 225 miles northwest of Baghdad.

The Oval Office meeting comes after Defense Secretary Donald H. Rumsfeld told Congress Thursday that Iraqi forces have "a way to go" before they are ready to take over the job from U.S. forces, adding that he opposes congressional calls for a timetable for withdrawing American troops.

Also Thursday, the top American commander in the Persian Gulf told Congress the Iraqi insurgency has not grown weaker in the past six months.

"I believe there are more foreign fighters coming into Iraq than there were six months ago," Gen. John Abizaid said.

In Iraq on Thursday, gunmen killed police Lt. Col. Majid Faisl Aziz when he was driving his car near western Baghdad's Amariyah neighborhood, police Capt. Talib Thamer said. Aziz was a member of the Interior Ministry's major crimes division.

Earlier, Iraqi troops clashed with gunmen in western Baghdad and at least one soldier was abducted, police 1st Lt. Akram al-Zubaie said.

The relentless carnage has killed more than 1,240 people since April 28, when al-Jaafari announced his Shiite-dominated government.

In an escalation of insurgent attacks in the capital, four car bombings killed at least 15 people and wounded 28 Thursday.

The force of the blasts — timed for when the capital's streets were most crowded — blew off store shutters, and the surrounding sidewalks were littered with debris, including charred vegetables and fruit. All told, Thursday's violence across Iraq left at least 20 people killed and 37 wounded.

There have been 480 car bombs in Iraq since the handover of sovereignty on June 28, 2004, according to an Associated Press count. At least 2,174 people have been killed and 5,520 have been wounded. Foreign fighters, mostly from Iraq's Arab neighbors, are believed to be responsible for many of them.

Iraq's shared border with Syria is named as the main point of infiltration. On Thursday, Secretary of State Condoleezza Rice again pressed Syria to follow through on a pledge to secure its border with Iraq.

But in Damascus, Syrian Foreign Minister Farouk al-Sharaa said Syria will ask Baghdad to provide evidence of militants infiltrating across their shared border. He also said a Syrian delegation will soon go to Baghdad to discuss restoring diplomatic ties that were severed in 1982.

On Thursday, American and Iraqi troops battled Al Qaeda-linked insurgents holed up in an upscale Baghdad neighborhood, killing at least five militants apparently waiting to carry out bomb attacks.

An Al Qaeda (search) affiliate, the Ansar al-Sunnah Army (search), claimed responsibility for a series of car bombs that killed dozens of Shiite Muslims over a 12-hour span in Baghdad. The bombings appeared designed to stoke sectarian tensions and push the country into civil war.

Sunni Arabs, who dominated Iraq for decades, lost power when Saddam Hussein, their last patron and a Sunni, was ousted. Their boycott of January's historic elections further sidelined them, and Sunnis make up the core of a violent insurgency.

But Sunni Arab participation in the political process is essential for Iraq's passage to democracy.

Parliament has until Aug. 15 to draft a new constitution, which will be put to a referendum two months later. If ratified, it will be the basis for a general election in December, giving Iraq its first, full-term elected government in decades.

The Associated Press contributed to this report.