A Japanese official mistakenly announced the launch of a North Korean missile instead of sending an alert about a strong earthquake that hit western Japan on Saturday morning.
An official at the transport ministry's western Osaka aviation bureau mistakenly e-mailed 87 airport offices that a North Korean missile had been launched, the ministry said.
The official was trying to send a message to check on possible airport damage immediately after the 6.3-magnitude earthquake hit the western Hyogo prefecture, it said.
But instead of sending an e-mail about the quake, the official mistakenly dispatched a pre-prepared alert ready to go in the event of a North Korean missile launch, it said.
The incorrect message was retracted six minutes later but at least one domestic flight was delayed due to the mistake, the ministry said.
Japan is on full alert ahead of an expected mid-range missile launch by North Korea, with Patriot missiles stationed in its capital to protect the 30 million people who live there.
In addition to PAC-3 batteries, Aegis destroyers equipped with sea-based interceptor missiles have been deployed in the Sea of Japan (East Sea).
On Wednesday, officials in the Japanese city of Yokohama were left red-faced after mistakenly announcing the launch of a North Korean missile to 40,000 followers on Twitter.
A 6.3-magnitude quake struck near Awaji island in the Seto Inland Sea southwest of the city of Kobe at 5.33am (2033 GMT on Friday), Japan's meteorological agency said, injuring at least 24 people and destroying some houses.