"We have Saudi Arabian jihadists in detention in Iraq and in Baghdad," Deputy Secretary of State Richard Armitage told Abu Dhabi TV in an interview.
"We've got a relatively few number of Saudis," he went on, "but we have Yemenis and Sudanese, Syrians."
He added that there was no evidence as to how they had got into Iraq, and no suggestion that the Saudi government had assisted them. He contrasted the attitude of the Saudis with that of Iran and Syria, whose borders he said were "particularly porous," and whose governments he accused of "not stopping fighters (crossing)."
Armitage did not comment on the circumstances of the fighters' detention or say how many were in U.S. custody. A State Department official who asked not to be named told United Press International, "Obviously we're in a situation of trying to verify identities, people may have false passports. ... I've heard the ball park figure of 15 and we're pretty sure some of them are Saudis."
Saudi officials say extremists may be getting across their 475-mile-long frontier with Iraq, but if so it is the responsibility of U.S. forces.
"We've done our duty on our side of the border by protecting it. The border is closed (on our side) ... If there's any infiltration happening it's because the United States as an occupying power has not done their job in protecting the border," Nail A. al-Jubeir, a spokesman for the Saudi Embassy in Washington, told UPI.
Armitage acknowledged that the Saudis had asked the United States to do more. "The government of Saudi Arabia has, as I recall, requested help from the American forces to try to help guard against that possibility (of infiltration) on the Iraqi side of the border," he said.
Al-Jubeir said the Saudis had no information about their nationals who might be in Iraq, which -- echoing the comments of U.S. and other officials -- he said had become a magnet for Islamic extremists from all over the world.
He said the United States had not formally approached his government with any concerns about Saudi extremists in Iraq or the border.
"We have not been informed about this by the U.S. government. We've only heard about it in news reports ... If there is a concern they should have brought it up with us," he said.
The State Department official said "I don't want to get into a 'he said, she said' situation here ... But the issue of Saudis coming into Iraq from Saudi Arabia, that has been raised with the Saudis." The official could not say at what level the contacts had been made and acknowledged that the Embassy in Washington might not have been aware of them.
Al-Jubeir said the Saudis had tightened their control along the border even before the war, concerned that elements of the Baathist regime might try to flee into Saudi Arabia or smuggle weapons of mass destruction out of the country.
But he acknowledged that the border was not airtight, "Can we guarantee that no one has slipped across the border? No."
He also said that Saudi extremists might have gone to Iraq to make war in Americans, but said it was more likely they had got there through neighboring states like Jordan. "Can we absolutely say that there are no Saudis there (in Iraq)? No ... Some of the cells we broke up in the northern areas (of Saudi Arabia) included foreign nationals -- Syrians -- who were trying to smuggle people out of the country, but that was more towards the Jordanian border."
One U.S. intelligence official, who asked not to be named, said it was hard to establish the numbers of foreign fighters present in Iraq. "It's more than dozens, it's probably in the hundreds," he told UPI.
"I don't think this is a case of people coming from third countries to loot, although you can't rule that out. Any time we have detainees we interview them and try to get to the bottom of their motivation," a defense official told UPI on condition of anonymity.