PHILADELPHIA — A British woman was charged Saturday in a security breach at Philadelphia International Airport that forced federal authorities to evacuate 2,000 passengers and delayed dozens of flights.

Police did not identify the 23-year-old woman, described only as a British national who allegedly walked through an unstaffed security lane in the airport's Terminal C Friday evening to reach her US Airways flight bound for San Juan, Puerto, Rico, in neighboring Terminal B.

"For some reason, she just decided to walk through it," said airport spokesman Mark Pesce.

It was the first airport security breach reported in Philadelphia since the federal government became responsible for airport security last Sunday. Philadelphia police took the woman into custody and charged her early Saturday with one count of defiant trespass, a misdemeanor punishable by up to one year in prison. British consular officials said they were aware of the case.

It was the second arrest of the day. A first-class passenger on a Philadelphia-bound flight from Boston was taken into custody for allegedly punching a female flight attendant.

Authorities, who monitored her movements on security cameras, removed her from the plane and searched both the aircraft and the two terminals with bomb-sniffing dogs. About 2,000 passengers had to be re-screened, while 60 flights suffered delays of up to 45 minutes.

"He smacked her into the bulkhead," FBI special agent Linda Vizi said.

William Thrasher, 26, of Acton, Mass., was charged with assaulting a flight attendant, who was treated at a local hospital and released. Thrasher remained in the custody of U.S. marshals, pending a federal court hearing Monday.

In Fort Myers, Fla., man was arrested after arguing with a National Guardsman and threatening to blow up the passenger terminal at Naples Municipal Airport.

Johnny Ray Gobin, 27, was charged Friday with threatening to discharge a destructive device, resisting an officer and breach of the peace. He was being held Saturday at Collier County Jail in Naples on $32,500 bond.