The Japan Coast Guard said early Thursday it falsely issued — and later retracted — a navigation warning to vessels claiming that North Korea had launched a missile on Wednesday.

The coast guard said the false warning was issued at around 8:45 p.m. Wednesday during a drill and was taken back about 40 minutes later. Another JCG official in another section noticed the mistake, it said.

There were no inquiries about the warning from ships although it was issued to vessels sailing in and around Japan as well as Southeast Asia, it added.

A coast guard official said the cause will be probed and measures will be taken to prevent any recurrence of such an incident.