A round of live ammunition was found inside the carry-on luggage of a Korean Air flight attendant at Incheon Airport earlier this week, leading to an investigation by airport police, officials said Thursday.

According to the Incheon International Airport Police Corps, airport officials discovered the 7.62 mm caliber bullet inside a flight attendant's bag during preboarding inspection on 7:30 a.m. en route to Bangkok on Tuesday. Police seized the bullet and had her take the flight as scheduled. The flight attendant was to be questioned upon her return.

Korean Air said Thursday that its internal investigation suggests that the flight attendant did not mean to bring the bullet onboard. It said she had recently visited her parent's home and took a pouch from her childhood that she took with her on the trip, which happened to contain the bullet.

The airline said it will cooperate with the police investigation and vowed to enhance safety education for all its employees.

This is not the first time a live bullet has caused a scare for airport authorities. In March, a cleaning staff member found two live bullets for a hunting rifle underneath the passenger seat of a Milan-bound aircraft of Korean Air. Police provisionally concluded it was not linked to any terrorism attempts.