The Port Authority of New York and New Jersey is secretly planning to deploy military-grade technology to keep the new World Trade Center safe from terrorism once it is completed, the New York Post learned.

The high-tech system of thousands of "intelligent" cameras and computer processors can recognize people's faces and retinas and then compare that information with databases such as terrorist watch lists, sources said.

The plans show that the Port Authority is taking every precaution at the twice-attacked site of 9/11.

Security measures at the 16-acre (6.5-hectare) site -- scheduled for a 2013 completion -- include the sensitive cameras alongside infrared and heat sensors that can be outfitted with explosive and radiation detectors.

And agency brass also are authorizing "artificial intelligence" computers that constantly track the behavior of people on the ground -- figuring out how to spot "unusual movements" that can be flagged for security personnel.

For example, cops could be dispatched if the computers detected someone deviating from the normal walkways or walking against the flow of pedestrians; jumping around or making erratic movements; or dropping a bag where people do not usually leave their luggage.

"What we're doing down there has never been done before," one agency official said.

The agency's system will be connected to the NYPD's Lower Manhattan Security Initiative, which has cameras and scanners spread around downtown.

The Defense Department contractor Behavioral Recognition Systems, based in Houston, will set up most of the system, which is expected to cost tens of millions of dollars.