NEW YORK (AP) — Three skydivers say they spent about four hours atop 1 World Trade Center in New York City before parachuting off it in a stunt that raised questions about security and left them facing felony charges.

James Brady, Marko Markovich and Andrew Rossig mentioned the four-hour timeframe in court papers Tuesday. They acknowledge making the Sept. 30 jump but pleaded not guilty to burglary and other charges.

They were arrested last month, shortly after a teenager was accused of climbing the as-yet-unfinished tower.

The incidents have spurred concerns about protections at the security-conscious trade center.

The Port Authority of New York and New Jersey owns the site and says it's secure. A spokesman says there have been physical, operational and policy changes since the daredevils' antics. He wouldn't give specifics.