American specialists are conducting DNA tests on human remains recovered along the Iraq-Syria border to determine if they belong to Saddam Hussein (search) or his sons Odai (search) and Qusai (search), Pentagon officials told Fox News.

The remains were retrieved from a convoy of vehicles that was attacked by U.S. forces in Iraq's western desert near Syria last week.

U.S. special forces shot several Syrian border guards during a firefight that broke out as the Americans chased the convoy of suspected Iraqi fugitives.

An undisclosed number of people were killed, wounded or captured in the attack against the convoy and the resulting border shootout in far western Iraq, Pentagon officials said Monday.

A senior defense official, speaking on condition of anonymity, said five Syrians were injured, three of whom were treated by U.S. forces. The official would not say on which side of the Iraq-Syria border the clash occurred. He said it did not appear that any Syrians were killed.

Officials released few details about the incident, which happened Wednesday. State Department spokesmen did not return telephone queries asking when casualties among the border guards would be returned to Syria and what its effect on U.S.-Syrian relations was likely to be.

Working partly on information from previously captured Iraqis, special operations soldiers attacked the convoy to stop what they believed were high-level fugitives linked to the fallen Iraqi government of Saddam, defense officials said.

About 20 people in the convoy were apprehended by the American troops, and most were released after it was determined they did not pose a threat, the senior defense official said.

The official would not disclose nationalities, but he said they were pursued as part of the U.S.-led coalition's effort to "seek out former regime members and leadership."

The official said "routine DNA testing will be done, if appropriate, based on all intelligence gathered." He said a site exploitation team would attempt to collect remains of the dead. He did not know the number killed and would not say how many vehicles were in the convoy.

It was unclear whether human remains had been found as of Monday. Also unclear who shot first in the exchange of fire with the Syrian border guards or the sequence of other events that led to the shooting.

Asked at an afternoon State Department news conference whether diplomats at the U.S. Embassy in Damascus were working to send back the Syrians, department spokesman Philip T. Reeker referred the question to the Defense Department.

The senior defense official said he knew of no U.S. government contact with Syria on the issue.

Intelligence that prompted the attack indicated the convoy included a number of higher-level Iraqis, although not necessarily Saddam, other officials said.

The British newspaper The Observer reported that the strike was based on an intercepted satellite phone conversation involving Saddam or his sons, but U.S. officials would not confirm the report. In addition, Defense Department officials told Fox News they did not believe Saddam or his sons were traveling in the convoy.

The special "Task Force 20" commando team was aided in the attack by fire laid down by an AC-130 gunship and other air support, one official said.

The chairman of the U.S. Senate Intelligence Committee said he would not be surprised to learn of Saddam's death because of "this very aggressive effort that we have been mounting" to locate Saddam and his loyalists.

"I will not be surprised at any military action that would lead to the possibility that we have now finally killed Saddam Hussein," Sen. Pat Roberts (search), R-Kan., told Fox News Sunday.

But, he added, "Until we have absolute proof, you have to assume he's alive."

The convoy was traveling a known smuggling route near the city of Qaim (search). It was unclear whether smugglers were among the casualties and how many Iraqis were captured or killed.

But a third Defense Department official said forensics experts went to the site to collect evidence, possibly for DNA testing.

Sen. Joseph Biden, ranking Democrat on the Senate Foreign Relations Committee, said that he and two other senators visiting Iraq do not know if Saddam was among those involved in the convoy attack.

Saddam and his sons are the top three on the U.S. list of most-wanted officials in Iraq, and coalition officials say the lack of evidence about their fate is fueling resistance to the occupation within Iraq. Biden echoed that concern Monday.

Biden said in a televised interview Monday that senators have "heard no confirmation that it was Saddam."

"It's awfully important that we find out whether he's dead or alive and get him captured," Biden said, "because he is, in his absence, in effect, still able to be intimidating, an intimidating factor."

U.S.-Syrian relations already had been strained over events in Iraq. Earlier this year, U.S. officials threatened sanctions against Syria because of allegations it harbored fleeing members of Saddam's deposed government and provided Iraq with military equipment.

The pressure led to speculation that Washington saw Damascus as the next U.S. military target after Iraq, but tensions eased after a May 3 visit to Damascus by Secretary of State Colin Powell.

Syrian President Bashar Assad later said his government had closed its border. He cited strong tribal connections between the two countries, however, and noted the vast desert areas on either side of the 300-mile Iraqi-Syrian border.

There were multiple reports over the weekend that Saddam's top aide, captured a week ago, had told U.S. interrogators Saddam and his two sons survived the war, and at least the sons had escaped to Syria. Other reports said they were forced to return to Iraq. The claims, attributed to Abid Hamid Mahmud al-Tikriti, could not be verified.

Mahmud was No. 4 on the U.S. list of the 55 most-wanted former Iraqi leaders, behind only Saddam and sons Qusai and Odai.

Some two dozen from the most-wanted list, and a number from another list of some 200 other fugitives, have been taken into U.S. custody over the weeks since the war to disarm Saddam ended.

A distant cousin of Saddam, Mahmud, 46, was the ace of diamonds on the U.S. deck of cards portraying leaders of Saddam's government, the highest official known captured when he was taken into custody a week ago. Often photographed standing behind Saddam, Mahmud was described by the U.S. Central Command as Saddam's national security adviser and senior bodyguard.

The Associated Press contributed to this report.