WASHINGTON, Jan. 13 — Saddam Hussein warned his Iraqi supporters to be wary of joining forces with foreign Arab fighters entering Iraq to battle American troops, according to a document found with the former Iraqi leader when he was captured, Bush administration officials said Tuesday.
The document appears to be a directive, written after he lost power, from Mr. Hussein to leaders of the Iraqi resistance, counseling caution against getting too close to Islamic jihadists and other foreign Arabs coming into occupied Iraq, according to American officials.
It provides a second piece of evidence challenging the Bush administration contention of close cooperation between Mr. Hussein's government and terrorists from Al Qaeda. C.I.A. interrogators have already elicited from the top Qaeda officials in custody that, before the American-led invasion, Osama bin Laden had rejected entreaties from some of his lieutenants to work jointly with Mr. Hussein.
Officials said Mr. Hussein apparently believed that the foreign Arabs, eager for a holy war against the West, had a different agenda from the Baathists, who were eager for their own return to power in Baghdad. As a result, he wanted his supporters to be careful about becoming close allies with the jihadists, officials familiar with the document said.
A new, classified intelligence report circulating within the United States government describes the document and its contents, according to administration officials who asked not to be identified. The officials said they had no evidence that the document found with Mr. Hussein was a fabrication.
The role of foreign Arab fighters in the Iraqi resistance to the American-led occupation has been a source of debate within the American government ever since the fall of Baghdad in April. Initially, American analysts feared that thousands of fighters would flood into Iraq, seeking an Islamic jihad in much the same way an earlier generation of Arabs traveled to Afghanistan in the 1980's to fight the Soviet occupation.
Military and intelligence officials now believe that the number of foreign fighters who have entered Iraq is relatively small. American military units posted along the border to screen against such an influx have reported that they have seen few signs of foreign fighters trying to cross the border.
In December, American military officials in Iraq estimated that foreign fighters accounted for no more than 10 percent of the insurgency, and some officials now believe that even that figure may be too high. Only 200 to 300 people holding non-Iraqi passports are being detained in Iraq by American forces, Brig. Gen. Mark Kimmitt, a military spokesman, told reporters in Baghdad in December.
"They're a threat, but the vast majority of the personnel that we have in detention for activities against the coalition, for activities against Iraqi citizens, remain personnel from this country," General Kimmitt said then.
But several officials said American forces were not certain of the accuracy of the American intelligence on the issue and acknowledge that there could be more foreigners inside the country than they currently think. "I've seen numbers from a couple hundred to a couple thousand," said one United States military official.
Another unresolved issue has been the level of coordination between foreign fighters and Iraqi insurgents, many of whom are former members of Mr. Hussein's security apparatus. Military and intelligence officials say they have detected cooperation at the tactical level, on individual attacks, but have less evidence of any coordination at a broader strategic level. Asked whether it appeared that Iraqi insurgent leaders had heeded Mr. Hussein's advice to keep foreign fighters at arm's length, officials said it was difficult to tell without more information on the full extent of the cooperation between the sides.
The use of suicide car bombings as a weapon in the insurgency has made American officials wonder whether Islamic militant fighters are behind some crucial attacks. The secular Iraqis who were members of Mr. Hussein's government are unlikely recruits for martyrdom, American officials said.
"There is no question that some foreign fighters have crossed into Iraq," observed Judith Yaphe, a senior research fellow at the National Defense University in Washington and a former Middle East analyst at the C.I.A. "How many? I don't think there are more than a couple hundred. Are they significant in the insurgency? I don't think they are. There are too many Iraqis who know how to do these things. The real question is the suicide bombers, that's not strictly speaking an Iraqi thing."
In addition to its value in understanding the nature of the enemy that American and allied troops now confront in Iraq, the document found with Mr. Hussein could also be grist for further debate about his relationship with Islamic fundamentalists.
As President Bush sought to build a case for war with Iraq, one of the most hotly debated issues was whether Mr. Hussein was in league with Mr. bin Laden and Al Qaeda. Senior officials at the Pentagon who were certain that the evidence of connections between Iraq and Al Qaeda were strong and compelling found themselves at war with analysts at the C.I.A. who believed that the evidence showed some contacts between Baghdad and the terrorist organization, but not an operational alliance.
At the Pentagon, several officials believed that Iraq and Al Qaeda had found common ground in their hatred of the United States, while at the C.I.A., many analysts believed that Mr. bin Laden saw Mr. Hussein as one of the corrupt secular Arab leaders who should be toppled.