Tokyo's Haneda airport suspended flights for about two hours Saturday morning after an infrared sensor system detected a person crossing a runway without permission, airport officials said.
It turned out to be an inexperienced worker.
The incident caused 70 departing and arriving flights to be delayed by as long as two hours, the officials said.
The system sensed an object at around 4 a.m. around the most seaward runway. A security camera picked up a man wearing an athletic shirt crossing the runway. It followed and then lost sight of him.
The Haneda airport office of the Land, Infrastructure and Transport Ministry closed the runway for about two hours pending locating the man, who was a 22-year-old part-time worker at Kyowakigyo, a company that cleans airplanes under contract with All Nippon Airways Co.
"I just wanted to exercise next to the sea. I wasn't used to working at airports," the man was quoted as saying by airport officials.
The ministry's airport office will issue a stern warning to the man as well as Kyowakigyo for violating airport control regulations. It will also check whether the man violated the Civil Aeronautics Law.
The airport's other two runways were closed from Friday night to Saturday morning for construction work.
