FBI Seeking 'Terror Trio' Believed Sent by al-Qaeda Boss

The FBI, CIA, and police are attempting to track down a trio of men they believe arrived in the US last month to launch a terror attack on the anniversary of 9/11. The men, who officials believe were sent by al-Qaeda boss Ayman al-Zawahiri, are suspected of plotting a car bomb attack in New York or Washington, officials said at a Manhattan press conference late yesterday. Zawahiri vowed earlier this year to seek revenge for the killing of Osama bin Laden. Details of the suspect attack followed earlier official reports of intelligence concerning an upcoming attack involving "credible, specific" information that has not yet been confirmed.

Sources told ABC News that investigators believe at least one of the men may be a US citizen, and that two of them may have some kind of official US documentation, such as green cards. Their identities are not known but investigators are poring through the names of individuals who entered the US in the last few weeks, likely from the tribal areas of Pakistan. Though information has not been confirmed, "we live in a world world where we must take these threats seriously and we certainly will," vowed New York City Mayor Michael Bloomberg. The FBI and Homeland Security has issued a bulletin with the information to some 18,000 law enforcement agencies in the US. (More Department of Homeland Security stories.)