NYPD also confirmed that all precincts citywide would be going through "terrorism alert drills" all day.

As the Big Apple approached its morning rush hour, police blockades could be seen at most of the city's major transit points.

Surveillance points at the George Washington Bridge, the Verrazano Narrows Bridge and the Brooklyn Bridge were spotted by TV traffic helicopters.

Major tunnels such as the Holland and Lincoln were also on a "heightened" state of alert.

Police were randomly stopping and searching vehicles entering the bridges and tunnels.

The three major airports, Kennedy, LaGuardia and Newark, are also reported to have stepped up security.

NYC's major commuter railroads, Metro-North and Long Island, have assigned armed police to travel the rails during the morning and evening commutes.

New Jersey Transit also announced that it was assigning armed state troopers to travel its system.

On a typical day, the NYC metropolitan area has more than 2 million people moving throughout the region's mass transit system.

The site of the 2001 terrorist attacks, lower Manhattan, has also seen increased police activity Thursday morning.

The New York Stock Exchange stepped up its own security in advance of its opening.

The U.S. Park Police has also gone on an emergency footing at the Statue of Liberty and nearby Ellis Island.

Overall, the atmosphere in the New York metro area, while anxious, remained calm.

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