The cache of documents recovered by the U.S. military in Iraq could provide important leads in the international war on terrorism, FBI Director Robert Mueller says.

There are 25 FBI agents, along with other U.S. counterterrorism officials, poring over the documents to find any links to terrorists, potential terror plots, evidence of weapons of mass destruction and activities of Iraqi intelligence agents.

"The FBI will continue to be vigilant in its counterterrorism efforts, both here and abroad," Mueller told reporters Thursday. "We are going through all Iraq documents as soon as we receive them, with CIA and others, that may help us to prevent another attack."

Mueller and Attorney General John Ashcroft also said at a news conference Thursday that the FBI had completed the questioning of nearly 10,000 Iraqis living in the United States. The interviews sparked fear among some Muslims and Arabs, but Ashcroft said they proved useful to U.S. troops in Iraq.

"Cooperation of the Iraqi-American people was essential to secure and safeguard our nation during this critical time," Ashcroft said.

Neither man mentioned any credible terrorist plots during the Iraqi war, something that had been a major concern before the conflict. Still, Ashcroft said, "We know that a significant terrorist threat persists, and we will persist in our efforts" to thwart it.

Mueller said FBI agents in Iraq are assisting in criminal investigations and in finding items stolen when the Baghdad museums were looted. The FBI is also putting alerts on the international police network about the stolen pieces and scanning the Internet to see if any are advertised for sale.

Ashcroft said the Justice Department and FBI also would help train Iraqi police in what he called "rule of law" enforcement techniques that stress respect for individual rights and privacy.

The interviews with Iraqis living in the United States produced 250 reports with pertinent information that assisted U.S. forces on the battlefield, Mueller said.

The Iraqis, many of whom opposed the rule of Saddam Hussein, helped U.S. officials plug gaps in other intelligence reports and locate weapons production and storage facilities, underground bunkers and tunnel systems, fiber optic networks and detention and interrogation rooms.

Mueller said only two complaints had been brought to his attention about the FBI interviews, a figure Muslim advocates say distorts the widespread fear felt by many Iraqi-Americans. The advocates also said that for every engineer or scientist interviewed by the FBI, there was a student or housewife with scant knowledge of the Iraqi regime.

"This community was not happy about a surprise visit from the FBI," said Dalia Hashad, the Arab, Muslim and South Asia advocate for the American Civil Liberties Union. "They answer the questions because they don't feel they have a choice."

Only a few dozen Iraqis were charged with immigration violations and none were arrested on other charges as part of the interviews, officials said.

Ashcroft said that five known Iraqi intelligence agents were expelled from the United States and the sixth, the son of a former diplomat, was arrested.