LOS ANGELES, Oct 28: 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, the network said on Wednesday.

Sources familiar with the tape - the authenticity of which US intelligence officials have not been unable to verify - said the man, who claims to be a US native and Al Qaeda supporter, warns that the "streets will run with blood".

The video appears to have been made as recently as late summer because the speaker discusses the Darfur conflict in Sudan, makes a reference to the Massachusetts same-sex marriage legislation and mentions the Sept 11 Commission, one United States intelligence official said.

ABC News vice-president Jeffrey Schneider said the network has not shown the video because its authenticity has not been verified by either independent analysts or government experts.

"We have worked with the CIA and the FBI, neither of whom have authenticated the tape," he said. "Obviously, it would be beyond irresponsible to broadcast this tape without first authenticating it."

The first disclosure of the tape by Internet columnist Matt Drudge prompted ABC to publicly acknowledge the video's existence before knowing whether it was real or fake.

Mr Schneider 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.

Asked about the tape at a campaign stop with President George W. Bush in Ohio, White House spokesman Scott McClellan told reporters, "The intelligence community is analyzing it, working to verify its authenticity."-Reuters