TOKYO • A bullet train travelling at a speed of 280kmh had a door open during its journey from Sendai in north-eastern Japan to Tokyo yesterday, but no passengers were injured, its operator East Japan Railway (JR East) said.

The incident in the morning lasted 40 seconds, with the door being completely open at one point.

It was a rare occurrence for the Japanese shinkansen, known for its safety and punctuality.

The problem was caused by a cleaner who forgot to close the car's device that manually opens and closes doors, said the train operator.

The conductor of the Hayabusa No. 46 bullet train made an emergency stop inside a tunnel in Shibata, Miyagi prefecture, after seeing indications that the ninth car's door was open.

The train resumed its journey 15 minutes later after a check.

The crew did not notice the cleaner's mistake as the door was closed when the train left Sendai at 10.15am. It is thought to have opened later.

Around 340 passengers were on board the train but nobody was standing near the door.

The bullet train arrived at its destination 19 minutes late. The incident delayed seven shinkansen services for up to 28 minutes, affecting about 3,300 passengers.

Japan's Transport Ministry urged JR East - which initially said the door was closed - to prevent a similar incident from happening again.

KYODO