ABC News has asked US security officials to examine a videotape it obtained in Pakistan of an English-speaking man threatening a massive attack on the United States in retaliation for its war against al Qaeda, the network said on Wednesday.
A source familiar with the tape - whose authenticity US intelligence officials have so far been unable to verify - said it contains a threat that the "streets will run with blood."
Responding to questions about the tape after its existence was first reported by Internet columnist Matt Drudge, ABC News vice president Jeffrey Schneider said the network has not aired the video because its authenticity has not been verified.
"We've been working around the clock in an effort to authenticate the content of the tape," Schneider told Reuters. "We have worked with the CIA and the FBI, neither of whom have authenticated the tape. Obviously, it would be beyond irresponsible to broadcast this tape without first authenticating it."
He said the tape was obtained from a source in Pakistan over the weekend and arrived in New York on Monday, where it was first viewed by network officials. He declined to discuss details of it.
Government officials in Washington confirmed that the CIA was analyzing the videotape. One official said it was not yet known whether the tape is authentic or a hoax.
The source familiar with the tape told Reuters that the hour long video features a man, whose face is concealed by a headdress, warning that a forthcoming attack on the United States would dwarf the suicide hijackings on September 11, 2001, that claimed nearly 3,000 lives.
According to the source, the man says, "The streets will run with blood" and says the United States has brought this on itself for electing a president who has declared war on Islam by attacking the former Taliban rulers in Afghanistan and waging war against al Qaeda.
The source added that linguistic experts who have examined the tape believe the man, who identifies himself only as "Assam the American," learned English at a very young age but is not a native speaker of the language.
"The intelligence community is analyzing it, working to verify its authenticity," White House spokesman Scott McClellan told reporters in Vienna, Ohio.
A US intelligence official said, "We have been unable to verify the tape's authenticity." The official added the review was continuing.
The question of whether the United States could be subjected to another September 11-type attack has been a major issue in the presidential campaign.