The two SH-60 patrol helicopters were conducting anti-submarine exercises on Saturday night near Torishima in the remote Izu island group
The next shipment will have about 75,000 vials of the vaccine, Kono told reporters. The government is planning to send out supplies to the rest of the country in the first week of March, he said.
Japan launched its inoculation drive on Wednesday, giving medical personnel the Pfizer-BionTech vaccine. It is the last of the Group of Seven grouping of industrialised nations to begin vaccinations.