With concern about security at the World Trade Center tower growing, a group of daredevils who parachuted off the skyscraper last year turned themselves in to the police on Monday afternoon, with one saying that the stunt had exposed the need for more vigilance at the city’s tallest tower.

“We just kind of walked in,” Andrew Rossig, 33, one of the parachutists, said before going with his lawyer to the First Precinct station house in Lower Manhattan. “It’s supposed to be the most secure building in the world. God forbid it was somebody else getting in there with a real intention to harm New Yorkers.”

Three of the men climbed to the top of the 1,776-foot tower at 1 World Trade Center at 3 a.m. on Sept. 30 and leapt off, while a fourth man kept watch below, defense lawyers said.

The three men opened parachutes and floated silently through the dark to land on West Street near Vesey Street. A security guard at the Goldman Sachs building spotted them folding up their chutes and called the police.