NEW YORK, USA (AP) — In an era when airline passengers can't even pass through a checkpoint with a bottle of shampoo, security experts were shocked  when a man swam ashore, scaled a fence and walked dripping wet into Kennedy Airport despite a $100 million system of surveillance cameras and motion detectors.

"Thank God it wasn't a terrorist, but we have to look at it as if we had another attack," said Isaac Yeffet, former chief of security for Israeli airline El Al. "That's the only way we'll improve the system."

The Port Authority of New York and New Jersey, which oversees JFK, quickly added police patrols to the airport perimeter and said it is investigating the security breach.

Authorities said the trouble began Friday evening when 31-year-old Daniel Casillo's jet ski ran out of fuel in Jamaica Bay. 

Casillo swam toward the bright lights of Kennedy's runway 4L, which juts out into the bay, then climbed an eight-foot fence that is part of the airport's state-of-the-art Perimeter Intrusion Detection System, authorities said.

Soaking wet, wearing a bright yellow life jacket, Casillo made his way across two intersecting runways — an estimated distance of nearly two miles — before an airline employee spotted him on a terminal ramp, authorities said.

According to the police report, Casillo told an officer: "I needed help!"

The intrusion-detection system, manufactured by defense contractor Raytheon, should have set off a series of warnings, said Bobby Egbert, spokesman for the Port Authority police officers union.

"This system is made specifically for those types of threats — water-borne threats," Egbert said. "It did not detect him climbing over a fence. It did not detect him crossing two active runways."

Port Authority police interrogated Casillo and charged him with criminal trespassing. Authorities said the airport grounds were clearly marked with no-trespassing signs that indicate it is a "restricted area for authorised personnel only."

Casillo was released for a court appearance on October 2. A man who answered the phone at the home of Casillo's girlfriend said the couple's lawyer had advised them to stop speaking to the media.