A teenage daredevil who sneaked to the top of the 1 World Trade Center tower pleaded guilty Wednesday in an escapade that fanned concerns about security at the nation’s tallest building.

Justin Casquejo admitted breaking a city misdemeanor law against scaling tall buildings without permission. He’s expecting a sentence of 23 days of community service for his March climb, which came about a week before three extreme-skydiving enthusiasts were arrested on charges of parachuting off the skyscraper at the heart of one of the country’s most security-conscious sites.

Together, the cases prompted a security shake-up at the World Trade Center.

Casquejo’s lawyer, Pamela Griffith, declined to comment Wednesday. The teen is due to be sentenced in September.

Casquejo, a 16-year-old climbing enthusiast from Weehawken, New Jersey, slipped through a small gap in a construction fence and then used a ladder, scaffolding, elevators and stairs to scale the unfinished tower early on March 16, according to court papers. Along the way, he got by an inattentive security guard, authorities said.

“I was walking around all night trying to figure out how to enter” the site, knowing it was a no-trespassing zone, Casquejo later told a police officer, according to court papers.

After spending about two hours atop the symbolic 1,776-foot-tall tower, Casquejo encountered a security guard as he descended.

The New York Police Department assigns more than 200 officers and uses surveillance cameras and other technology to protect the 16-acre World Trade Center site’s perimeter. Port Authority of New York and New Jersey police and private security agents protect the inside. Ultimately, plans call for a $40 million system of barriers and checkpoints around the lower Manhattan site, which the Port Authority owns.

After Casquejo’s climb and the skydivers’ arrests, Mayor Bill de Blasio vowed to deepen the city’s work with the Port Authority to safeguard the site, and Sen. Charles Schumer called for federal officials to review security there.

The building’s private head of security resigned, the guard Casquejo eluded was fired and the Port Authority brought in a company that guards its airports to handle security at trade center entrances and monitor security systems there.

The Port Authority declined to comment Wednesday.

Meanwhile, the skydivers and someone accused of helping them on the ground have pleaded not guilty to various charges in the Sept. 30 leap from 1 World Trade Center.

(AP)