The pilot whose gun discharged in the cockpit of a U.S. Airways flight from Denver to Charlotte, N.C., has been placed on leave pending an investigation, USA Today reported.

No injuries were reported after the incident on the Saturday flight from Denver to Charlotte, N.C., and the plane has been taken out of service.

Airline and federal officials said Flight 1536 was not in any danger as a result of the incident, which occurred about 9:50 a.m. MDT.

Officials said the unnamed pilot was allowed to carry the weapon as part of the Transportation Security Administration's Federal Flight Deck Officer program. It was created after the Sept. 11, 2001, terrorist attacks.

The program allows eligible crew members — including pilots, navigators and flight engineers — to use a firearm to defend against any act of air piracy or criminal violence.

The TSA said the Federal Air Marshals Service takes the matter seriously.

The pilot may have mishandled the firearm. The bullet pierced a hole in the cockpit wall, a federal air marshal and gun safety expert said Tuesday.

"This is an extremely safe and reliable weapon," said Greg Alter of the Federal Air Marshal Service. "It's not going to discharge on its own is the bottom line."

The pistol — a .40 caliber semiautomatic H&K USP — discharged shortly before noon aboard the plane with 124 passengers and five crew members. The plane was at roughly 8,000 feet and approaching to land. Photos show a small entry hole in the lower side of the cockpit wall and a small exit hole on the exterior below the cockpit window.

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The Associated Press contributed to this report.