According to the MSDF, the blaze broke out in the engine room at around 9:40 a.m. local time on the minesweeper Ukushima, which was sailing about 2 kilometres north of Oshima in Munakata city, Fukuoka Prefecture, reports Xinhua news agency, quoting public broadcaster NHK.

One crew member left behind in the engine room had inhaled smoke and complained of a sore throat and was transported to a fishing port in Munakata city, where he was handed over to an ambulance, the report said.

As of 2:20 p.m. local time, NHK footage showed that grey smoke was seen rising from one of the two funnels at the rear of Ukushima.

The MSDF and the Japan Coast Guard are working to extinguish the fire and are investigating the incident.

Minesweepers are vessels tasked with removing mines laid in the sea, and Ukushima had about 40 crew members on board.