Thousands of U.S. and Iraqi troops fanned out across the fields of southern Iraq in scorching temperatures Thursday as the military said it remained determined to find two missing U.S. soldiers after the body of a third was pulled from a river.

Also Thursday, a car bomb targeting a funeral procession in the turbulent city of Fallujah killed at least 21 people, police and medical officials said.

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The military confirmed Thursday that the body found a day earlier in the Euphrates River south of Baghdad was that of Pfc. Joseph Anzack Jr., who had been missing since militants ambushed his unit nearly two weeks ago.

A commanding officer identified the remains recovered from the river, but DNA tests were still pending, military officials told Anzack's family.

"They told us, 'We're sorry to inform you the body we found has been identified as Joe,"' the soldier's aunt, Debbie Anzack, said Wednesday. "I'm in disbelief."

Anzack, 20, vanished along with the two other soldiers after their combat team was ambushed May 12 about 20 miles outside Baghdad. Five others, including an Iraqi, were killed in the ambush, subsequently claimed by Al Qaeda.

"We can confirm that we have recovered the remains of Pfc. Anzack," Lt. Col. Josslyn Aberle, a military spokeswoman, said Thursday.

The attack triggered a massive search operation in the area south of Baghdad known as the triangle of death for the insurgent activity there.

On Thursday, soldiers proceeded with their mission, despite Anzack's death. One unit searched chicken coops and trudged through mud, canals and tall reeds in the brutal heat.

"The search continues," said Lt. Col. Christopher Garver, a U.S. military spokesman.

Members of Anzack's platoon choked back tears at news of his death and said they would not stop looking for the other two missing soldiers.

"We can't leave them behind. I just hope that they have enough faith to keep them going. What they're going through right now, I can't imagine," said Pfc. Sammy Rhodes, 25, of Albuquerque, N.M.

Spc. Daniel Seitz, 22, from Pensacola, Fla., said he was trying to stay strong and push ahead with the search.

"It just angers me that it's just another friend I've got to lose and deal with, because I've already lost 13 friends since I've been here and I don't know if I can take any more of this," he said.

Aberle denied reports that a second body had been found and was being examined to determine if it was that of another of the missing soldiers. "The reports of a second set of remains being found is a false report," she said.

The U.S. military also announced Thursday that two U.S. soldiers were killed the day before while conducting combat operations in Iraq's volatile Anbar Province. Those deaths, along with the deaths of nine other troopers announced Wednesday, brought the American death toll for the month to at least 82. Last month, 104 U.S. troops were killed in Iraq.

The increase in U.S. deaths come at a difficult moment for Washington, where the administration of President Bush and Congress are struggling to agree on funding for the unpopular war. The search for the captured soldiers has also taken thousands of troops out of the pool of forces for the Baghdad security crackdown.

In other violence, a parked car bomb exploded Thursday morning in Fallujah, 40 miles west of Baghdad, as a funeral procession passed by for a man who worked against Al Qaeda in Iraq.

The blast killed 21 people and wounded 50 others, police and medical officials said. The funeral was being held for Alaa Zuwaid, a 60-year-old restaurant owner who was part of a tribe that had formed an alliance with other tribal leaders against Al Qaeda.

Zuwaid was killed earlier Thursday morning when unknown militants shot him in front of his house, police said. His 25-year-old son was killed by militants nearly a month ago as he walked down the street.

In Sulaiman Bek, 75 miles south of the northern city of Kirkuk, a roadside bomb an Iraqi police convoy killed six police officers Thursday morning, Iraqi police said.

Nationwide, at least 104 people were killed in sectarian violence or found dead Wednesday, including 32 who died in homicide bombings.

Insurgents in Baghdad attacked a convoy of U.S. diplomats and their military escort with small arms fire on Wednesday morning, the U.S. military said in a statement.

Apache helicopters rushed to the scene and fired at several of the armed attackers, the military said. U.S. troops then arrived to secure the area and allow the convoy to leave, the military said.

Thousands of U.S. and Iraqi forces have been involved in the search for the soldiers ambushed and captured May 12.

Maj. Gen. William Caldwell, the chief U.S. military spokesman in Iraq, said the remains, later identified as those of Anzack, were recovered by Iraqi police.

Witnesses said police using civilian boats searched for other bodies on the river in Musayyib, about 40 miles south of Baghdad, and U.S. troops intensified their presence on a nearby bridge as helicopters flew overhead, witnesses said.

Hassan al-Jibouri, 32, said he saw the body with head wounds and whip marks on its back floating on the river Wednesday morning. He and others then alerted police.

The remaining missing soldiers are Spc. Alex R. Jimenez, 25, and Pvt. Byron W. Fouty, 19.

At Jimenez's father's home in Massachusetts, a yellow ribbon also was tied on the front door. Ramon Jimenez, who speaks Spanish, said through a translator in a cell phone conversation that he has been helped by the support of friends and family.

"The hope is very high that God is going to give Alex back to him," said Wendy Luzon, a family friend who translated the conversation and has been serving as a spokeswoman.

Iraqi Prime Minister Nouri al-Maliki, meanwhile, announced he was ready to fill six Cabinet seats vacated by politicians loyal to radical anti-American Shiite cleric Muqtada al-Sadr in a mass resignation last month.

Al-Sadr, who went into hiding in Iran at the start of the Baghdad security crackdown, ordered his ministers to quit the government over al-Maliki's refusal to call for a timetable for U.S. withdrawal.

In Washington, National Security Council spokesman Gordon Johndroe said U.S. and Iraqi officials were planning to increase again the number of Iraqi security forces to help quell violence in the country.

About 337,000 Iraqi police and soldiers had been trained and equipped as of May 9, according to Defense Department statistics. Officials hope to have the currently planned 365,000 in place by the end of the year, Brig. Gen. Michael Jones, deputy director for political-military affairs in the Middle East for the Joint Chiefs of Staff, told lawmakers Tuesday.

Complete coverage is available in FOXNews.com's Iraq Center.