The person on the tapes SOUNDS like an American.  This could be a hoax.
Terrorism's greatest weapon is FEAR.
 

 
WASHINGTON — U.S. intelligence agencies are analyzing a videotape that threatens an assault on the United States that would "dwarf" the Sept. 11 attacks, FOX News learned.

The tape was handed to the Central Intelligence Agency and National Security Agency by ABC News two days ago, multiple government sources said. ABC is said to have received the tape last weekend from a terrorist source in Waziristan, a region in Pakistan near the Afghan border where the Taliban and Al Qaeda are believed to be holed up.

The government set 3 p.m. EDT interagency deadline to determine the authenticity of the tape, officials told FOX News.

The speaker on the video is disguised but speaks "alarmingly" fluent English in an American accent, leading some U.S. officials to believe that the voice belongs to Adam Yahiye Gadahn. Gadahn, who also goes by the names Adam Pearlman and Abu Suhayb Al-Amriki, is a 25-year-old Southern Californian fingered by the FBI for possible ties to Al Qaeda.

In May, the FBI announced Gadahn had ties with senior Al Qaeda lieutenant Abu Zubaydah in Pakistan, and that had attended terrorist training camps in Afghanistan and served as a translator for the terror network.

"Adam Yahiye Gadahn being sought in connection with possible terrorist threats against the United States," the FBI said in an announcement in May. "Although the FBI has no information indicating this individual is connected to any specific terrorist activities, the FBI would like to locate and question this person. He should be considered armed and dangerous."

"He is known to have performed translations … as part of the services he has provided to Al Qaeda," the FBI said.

Gadahn, whose whereabouts unknown, is believed to have knowledge of an imminent attack on the United States and is being pursued by federal officials.