ST. LOUIS (AP) — An officer at St. Louis' busiest airport fatally shot a man who wielded a knife early Friday morning outside the doors of a terminal, police said. No one else was injured.

The shooting at St. Louis Lambert International Airport happened around 1 a.m., St. Louis County Police spokesperson Vera Clay said.

The area is located near the light rail line that transports travelers to the terminal and isn't behind a security checkpoint, according to maps of the airport posted on its website.

The rail line to Terminal 1 was briefly closed, with shuttles taking people from other drop-off points, but was reopened later Friday morning. The airport remained open.

Clay said officers had noticed the man, who was not identified, in an area where he should not have been and refused to leave.

Vera said the man showed officers a knife when they tried to get him to move. Officers used Tasers but the man continued to advance toward the officers and one of them fired their gun, fatally wounding the man, Vera said.

The two officers were part of the airport's police department and had 6 months and 1 year of service on the force respectively, as well as earlier law enforcement experience, St. Louis County police said in an emailed statement.