WASHINGTON -- Attorney General John Ashcroft urged Americans to adopt "the highest state of alert" in the search for 16 men possibly linked to Osama bin Laden's terrorist network and believed to have planned an attack against the United States or its people in Yemen.
The FBI said Tuesday it based an unusually detailed public warning on information from interviews by U.S. officials with detainees in Guantanamo Bay, Cuba, and in Afghanistan. Three earlier alerts were vague as to the date of any potential attack.
The latest, listing names of possible terrorists and warning of an attack "on or around" Tuesday, did not specify any possible targets.
The warning identified the possible ringleader as Fawaz Yahya al-Rabeei, a Yemeni citizen born in 1979 in Saudi Arabia. A U.S. official said al-Rabeei is believed to have links to al-Qaida but is not believed to have been involved in the attack against the USS Cole in the Yemeni port of Aden in 2000.
Ashcroft, in San Antonio for a speech, described al-Rabeei and the 15 others in the warning as "individuals who may be associated with Osama bin Laden and the al-Qaida network." He did not elaborate.
The FBI published photos of al-Rabeei and 12 of the others on its Web site, www.fbi.gov. The FBI asked police "to stop and detain" any of those in the alert and said they should be considered extremely dangerous.
Officials acknowledged they did not know whether al-Rabeei was in the United States and could not be sure even that he was alive. A hurried review of immigration records showed no indication he had ever been in the United States, a Justice Department official said.
Internationally, allies were trying to determine where al-Rabeei and his associates had traveled recently, but those efforts were being hampered by the numerous aliases the men might be using. The FBI listed at least 14 for al-Rabeei alone, including "Furqan The Chechen."
"I want to encourage all law enforcement officials, and, frankly, all Americans everywhere to be on the highest state of alert in regard to these individuals," Ashcroft said. "I encourage individuals to report anything that they consider to be suspicious."
One law enforcement official said the threat information was corroborated to an extent by multiple sources in Cuba, Afghanistan and in allied governments.