We expect security in sports stadiums around the country will be exceptionally tight this weekend. Besides the usual fears, fans now have another threat to process: Trucks delivering radioactive bombs to open-air stadiums in seven U.S. cities where professional teams operate.

The U.S. Department of Homeland Security has passed along the threat but remains skeptical about its reliability. Government officials believe the claim, aimed at stadiums in New York, Miami, Atlanta, Seattle, Houston, Oakland and Cleveland, is a hoax. It was posted on an English-language Web site called www.thefriendsociety.com.

But nevertheless, agency officials erred on the side of openness and passed along the threat information to state and local officials. "The department views the threat with strong skepticism," a spokesman told news outlets. "There is no credible intelligence to suggest such attacks."

The nation's threat level remains at yellow. Airlines have remained at orange ever since the plot to blow up U.S. bound planes was exposed in August.

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