A staff member for a Pennsylvania congressman was arrested Friday for carrying a concealed weapon inside the Capitol complex.

A Capitol Police spokeswoman said Ryan Shucard, press secretary for Rep. Tom Marino, R-Pa., entered the Cannon House Office Building at 9:15 am carrying a Smith & Wesson 9 mm handgun and magazine. The weapon, which wasn't loaded, was discovered during a routine X-ray security screening required of all congressional staffers.

Shucard was immediately taken into custody and arrested without incident, said police spokeswoman Lt. Kimberly Schneider. He was charged with carrying a pistol without a license, which is a felony.

Bill Tighe, the congressman's chief of staff, told the Washington Examiner that Shucard has been placed on unpaid leave. Shucard began working in Marino's office in May.

Tighe said it is believed Shucard forgot he was carrying the gun, saying that police told the congressman's office the Capitol "did not face a threat in any way."

This isn't the first time a congressional staffer has been arrested for carrying a gun at the Capitol. In 2007, an aide to former Sen. James Webb, D-Va., tried to take a loaded pistol into a Senate office building. The staffer said the weapon belonged to the senator and that he forgot he was carrying it.