The officials said they had obtained intelligence indicating that senior Iraqi leaders were traveling in the convoy. They suggested that the intelligence might have come from an intercepted telephone conversation or an informant. The attack took place Wednesday near the Syrian border in western Iraq.

There was no evidence so far, the officials said, to support the idea that Mr. Hussein or his sons might have been killed in the raid, and some officials were doubtful that they were. But they said intelligence teams, including DNA experts, were at the site to review the wreckage and assess the evidence.

Officials declined to say how many people, or vehicles, were in the convoy, but they said it had been completely destroyed. If DNA evidence was the only method of determining who had been killed, it could take days to get the results.

A British newspaper, The Observer, disclosed the attack in today's issue and said it had been an attempt to kill Mr. Hussein. The Pentagon and the United States Central Command declined today to discuss that report, and American officials who agreed to discuss it on the condition of anonymity said the United States had never been certain that Mr. Hussein or his sons were in the convoy.

Still, administration officials said the strike underscored a growing belief among American intelligence officials that Mr. Hussein and his sons were not killed during the war and have remained in Iraq. The attack on the convoy showed the pressure of a stepped-up manhunt after information provided by a Hussein confidant who was detained last week.

The aide, Abid Hamid Mahmoud al-Tikriti, 46, who had served as the Iraqi leader's secretary and bodyguard, told his American interrogators that Mr. Hussein and his sons, Uday and Qusay, survived the war, and that he himself traveled to Syria after the conflict with Mr. Hussein's sons before being expelled, according to Defense Department officials who have said they have not been able to corroborate those claims.

A senior administration official said tonight that President Bush had been aware of the strike before it occurred but did not have to approve it. The official said a team was moving in to try to recover the DNA of those in the convoy, but it was unclear if they had yet arrived at the scene. 

Some American officials described the attack as having been in the same category as the March 19 and April 7 attacks on compounds where Mr. Hussein and his sons were believed to be hiding. American intelligence analysts now believe that Mr. Hussein and his sons probably survived both those attacks.

A senior administration official described the intelligence that led to the Wednesday attack as a good lead. But another administration official said, "I have no information that leads us to believe we got Saddam." A military officer said intelligence reports that Mr. Hussein or his sons might have been in the convoy might have been based more on hope than evidence.

"There might be people crossing their fingers, but it's just like a year ago, when they were crossing their fingers" in the hopes of capturing Osama bin Laden, one military official said. Mr. bin Laden, Al Qaeda's leader, is still believed to be alive after 21 months in which he has been the target of an intense manhunt.

In a television interview today, King Abdullah of Jordan said he had heard reports several days ago that Mr. Hussein and his sons were in Iraq's western desert region. But he said he had heard many reports of their whereabouts in recent weeks and months and did not know if this one was accurate.

"It's like Elvis," King Abdullah said on the ABC News program "This Week." "There's a lot of sightings of him all over the place."

Members of the Senate Intelligence Committee, including the chairman, Senator Pat Roberts, Republican of Kansas, said in television appearances today that they had not been informed of any new missile strike aimed at the Iraqi leader. Still, Senator Roberts, speaking on "Fox News Sunday," said, "I will not be surprised at any military action that would lead to the possibility that we have now finally killed Saddam Hussein."

Senator John D. Rockefeller IV of West Virginia, the ranking Democrat on the committee, said on the same program that any confirmation of the death of Mr. Hussein would serve to undercut the morale of fighters who are staging hit-and-run attacks on American soldiers and at the same time instill confidence among the broader Iraqi public.

The search for Mr. Hussein has been led by Task Force 20, a secret military organization that is working closely with American intelligence agencies and whose members include special Army and Navy counterterrorist teams.

The United States is flying U-2 spy planes and RC-135 electronic eavesdropping aircraft over Iraq on a regular basis. Both are able to scoop up electronic emissions and pinpointing locations for strike aircraft or Predator drones, which are piloted by remote control and can be either armed or unarmed; they are being flown from an air base in Iraq.

One senior administration official noted that Hellfire missile attacks on convoys by the Predators were rare and would not have been carried out except on the basis of good intelligence about an important target.

Other officials said that the United States had obtained good reconnaissance photos showing that the convoy had been destroyed, but that those photographs did not clarify who had been in the wreckage.

"Although we do have good intelligence, you don't know if you have someone until you've seen the analysis from the ground," said one senior American officer.