An Internet message claiming that seven NFL stadiums will be hit with dirty bombs this weekend was met with "strong skepticism" Wednesday by government security officials.
With nothing to indicate an imminent attack, local authorities and stadium owners were alerted "out of an abundance of caution."
Dated Oct. 12, the posting was part of an ongoing conversation titled "New Attack on America Be Afraid." It appeared on a Web site called "The Friend Society," which links to various online forums and off-color cartoons.
The message said trucks would deliver radiological bombs to stadiums in New York, Miami, Atlanta, Seattle, Houston, Oakland and Cleveland - and that Osama bin Laden would later claim responsibility.
Homeland Security spokesman Russ Knocke said the threat was being viewed "with strong skepticism," but the agency contacted the NFL, local authorities and stadium owners "out of an abundance of caution." The NCAA, which oversees college athletics, said it was also notified.
"The department strongly encourages the public to continue to go about their plans, including attending events that involve large public gatherings such as football games," Knocke said.
FBI spokesman Richard Kolko said the threat was "questionable" and was discussing it with the NFL as "part of our routine discussions this week."
NFL spokesman Greg Aiello said stadiums around the country "are very well protected through the comprehensive security procedures we have in place, including secure facility perimeters, pat-downs and bag searches."
Officials were made aware of the Web posting on Oct. 16. The threat was timed to be carried out on Sunday, Oct. 22, marking the final day in Mecca of Ramadan, the Islamic holy month.
"The death toll will approach 100,000 from the initial blasts and countless other fatalities will later occur as result from radioactive fallout," according to a copy of the posting obtained by The Associated Press.
It said al-Qaida would automatically be blamed for the nearly simultaneous attacks and predicted, "Later, through al-Jazeera, Osama bin Laden will issue a video message claiming responsibility for what he dubbed 'America's Hiroshima.'"
The posting noted that all but one of the stadiums - Atlanta - are open-air arenas, adding: "Due to the open air, the radiological fallout will destroy those not killed in the initial explosion." The retractable roof in Houston has been closed for all games so far this season.
Several NFL teams and stadium owners acknowledged that they were in contact with federal officials, including the New Jersey Sports and Exposition Authority, which operates Giants Stadium, the home of the Jets and Giants.
In Indianapolis, where the Colts were preparing for a home game this weekend, head coach Tony Dungy said, "I've been waiting for this to happen for a couple of years now and you try and handle the security and put it out of your mind."
"We'll let the security people do their job, and we'll do our job," Dungy said. "We've got a lot of confidence in NFL security and our own security here."
Raiders senior administrator Artie Gigantino said there would be no noticeable increase in security this weekend at Oakland Coliseum.
"But if we say we are going to do something different or obvious," he said, "it wouldn't be security anymore."
Minnesota linebacker Napoloeon Harris, who will play with the Vikings this Sunday in Seattle, said he's never felt threatened as a player, but understands why the league was alerted despite the threat's questionable credibility.
"After 9/11, you've really got to take everything serious," he said. "You really can't take for granted your security. That's just the way I look at it. Especially something of that magnitude."
Authorities traced the site's Internet provider back to Voxel Dot Net Inc., which has support and engineering staff based in Troy, N.Y. A man who answered the phone at Voxel, who declined to give his name, said he was unaware of the posted threat on the Web site and refused further comment.
The author of the threats, posted at 9:31 p.m. EDT on Oct. 12, identified himself online as "javness."
"In the aftermath civil wars will erupt across the world, both in the Middle East and within the United States," javness wrote. "Global economies will screech to a halt. General chaos will rule."
The nation's general alert level remains at yellow, signaling an elevated risk of an attack. The threat level for airline flights is at orange, where it has been since a foiled plot to bomb U.S.-bound commercial jets was revealed on Aug. 10.
Associated Press sports writers Dave Goldberg and Ralph Russo in New York, Kristie Rieken in Houston, Josh Dubow in Alameda, Calif., Dave Campbell in Eden Prairie, Minn. and Michael Marot in Indianapolis contributed to this report.