According to the Kyodo news agency, a cargo ship and a gunboat – both said to be from North Korea – were detected in the Japanese exclusive economic zone in the Sea of Japan on 23 August.
The vessels soon left the area but returned on the next day, with the gunboat having approached a Japanese patrol ship. A man in a uniform on board the gunboat pointed a weapon toward the Japanese sailors but no gunfire followed.
“We believe that the vessels are likely to be from North Korea. We have lodged a strong protest via the embassy in Beijing", Suga said, as quoted by Kyodo.
The Japanese authorities believe that the vessels were involved in North Korea’s illegal fishing in Japan's exclusive economic zone.