A United Airlines flight from Denver to San Diego was delayed Thursday after a live bullet was discovered aboard the plane before departure, prompting passengers to deplane while security personnel swept the aircraft.

United Flight 1302 was preparing to leave Denver International Airport when the bullet was found during routine checks before the plane taxied to the runway.

The crew said at the time that it did not know how the bullet got aboard the aircraft or where it came from.

United Airlines confirmed the incident in a statement, saying the Boeing 737-900 was carrying 178 passengers and six crew members.

The airline directed additional questions about the incident to the Transportation Security Administration (TSA).

Original reporting: Fox News (HLL/CB) — read the source article.