In an apparent Sept. 11 communiqué broadcast on ABC News, an al Qaeda operative threatens new attacks against cities in the U.S. and Australia.
"Yesterday, London and Madrid. Tomorrow, Los Angeles and Melbourne, Allah willing. And this time, don't count on us demonstrating restraint or compassion," the tape warns. "We are Muslims. We love peace, but peace on our terms, peace as laid down by Islam, not the so-called peace of occupiers and dictators."
American intelligence officials believe the man who appears on the tape to be Adam Gadahn of Orange County, Calif. Last year, Gadahn delivered a similar taped communiqué for al Qaeda. That tape was later deemed authentic.
On the new tape, delivered to ABC News in Pakistan on Saturday, Gadahn's message contains a very pointed al Qaeda threat against Los Angeles and Melbourne. U.S. intelligence officials are closely studying the tape, looking for clues that might lead them to the man who made it. One clue ABC heard on the tape was the sound of many children in a hallway.
This morning, Los Angeles Police Chief William Bratton acknowledged his city is a target for terrorists
"We're the entertainment capital of America," Bratton said. "All the negative images of America that these people hate are represented here in Los Angeles."
On Sunday, Mayor Antonio Villaraigosa and the city's police department released a statement also acknowledging that Los Angeles is a target for terrorists, but adding there are no known, credible threats against the city. They labeled the tape an instrument of al Qaeda propaganda.
"The statement broadcast this [Sunday] morning on 'Good Morning America' should come as no surprise to anyone. The statement was meant to instill fear, and fear is the most important weapon the terrorists possess."
The taped diatribe lasts 11 minutes. Like past tapes, it appears to include the same graphics and production techniques recognized by U.S. officials as part of al Qaeda's standard propaganda production. In this tape, the speaker levels threats against the United States and Great Britain.
"Don't believe the lies of the liars at 1600 Pennsylvania Avenue and 10 Downing Street," Gadahn insists. "They have dispatched your sons and daughters to die lonely deaths in the burning deserts of Iraq and the unforgiving mountains of Afghanistan."
Only a few years ago, Gadahn was a Southern California teenager with interests in the environment, the Los Angeles Dodgers and heavy metal music.
His family says he converted to Islam at an Orange County mosque. There, officials say, Gadahn came under the influence of militants who took him to Pakistan. Officials believe Gadahn is hiding in Pakistan with an Afghan wife.
He has since emerged as an al Qaeda propaganda tool. His latest message warns Americans an attack is imminent unless the United States stops its operations in Iraq and Afghanistan.
"We love peace, but when the enemy violates that peace or prevents us from achieving it, then we love nothing better than the heat of battle, the echo of explosion and the slitting of the throats of the infidels," the tape says.
As for the rest of the tape, the young man attempts to dispel any rumors or reports of bin Laden being deceased. He closes his tape by invoking the names of the Sept. 11 hijackers.
"Every one of us is Mohammed Atta," he says.
ABC News' Chris Isham, David Scott, Gretchen Peters, Krista Kjellman and Avni Patel contributed to this report.