A passenger opened a door on a South Korean plane shortly before it landed, officials have said.
Some people on board the Asiana Airlines flight tried to stop the person from opening the door but it was eventually opened partially, the transport ministry said.
The plane, with 194 people on board, was heading to the southeastern city of Daegu from the southern island of Jeju.
The flight normally takes around an hour.
It was not disclosed how long the door was open.
The flight later landed safely at Daegu International Airport.
The incident terrified some passengers but no one was injured, though some passengers were assessed at a hospital, Asiana and government officials said.
Person who opened door arrested
The transport ministry later said the person who opened the door had been detained.
Pictures showed officers in plain clothes arresting a passenger.
The ministry said police had taken the passenger into custody and were investigating a possible violation of aviation safety laws.
Their motive was not known.
The passengers included teenage athletes who plan to attend track and field competitions in Ulsan, another southeastern city.