9/11 Anniversary Terror Threat Probed, NYPD on High Alert

New Yorkers will see extra subway bag checks, vehicle checkpoints and plenty of extra police officers in the city on the 10-year anniversary of the Sept. 11, 2001 terrorist attacks.

U.S. intelligence sources have reported a "credible but unconfirmed" threat that Al-Qaeda may attempt to detonate a vehicle bomb in Washington or New York. Authorities have been warned that a handful of individuals may have entered the U.S. in recent days as part of the plot, which officials said originated from the tribal areas of Pakistan along the Afghan border. One of them may be a U.S. citizen, the Washington Post reports.

As a result, the NYPD is on high alert. NYPD Commissioner Raymond Kelly has said police will set up additional vehicle checkpoints around the city, increase bag checks on the subway, and keep a closer eye on bridges and tunnels.

Mayor Michael Bloomberg has cautioned that the threat information has not been verified.

Sources: Washington Post , NBC New York , and New York Times .