New York ? Visitors to the complex that eventually will fill the World Trade Center site might have to submit to iris scans or thumb print analysis to get into buildings, while smart cameras try to match their faces to a photo database of known terrorists. Well-paid armed guards would be on patrol and sensors would test the air for lethal gases.

Preliminary details of a plan to make the redeveloped 16-acre site as terrorism-proof as possible were provided to The Associated Press this past week by former FBI agent James Kallstrom, Gov. George Pataki’s senior counterterrorism adviser.

Kallstrom and city and federal officials are aiming for a higher standard of security than is currently in use for public spaces around the nation.

Construction is set to begin this spring on a memorial to the 9-11 terrorist attacks and the Freedom Tower, a 1,776-foot skyscraper that some say is having trouble attracting tenants because of security concerns. A transit hub, performing arts center and more office towers also are planned.