Japanese Defense Ministry officials say a Chinese naval vessel has sailed through Japan's territorial waters off the southern prefecture of Kagoshima. They say they have conveyed their concerns to Beijing through diplomatic channels.
On Friday, the officials said a Chinese survey ship was spotted south of Yakushima Island at around 8:40 p.m. on Wednesday. They say it was sailing within Japan's contiguous zone toward the country's territorial waters.
They say it was then seen sailing within the contiguous zone further west, off Kuchinoerabu Island at around 1:20 a.m. on Thursday.
The ministry has concluded that the vessel passed through Japanese waters.
This is the fourth time that a Chinese naval vessel has been confirmed to have entered Japanese territorial waters, and the first since July 2017.
The ministry also said two Chinese naval ships and a Russian naval vessel passed the Tsushima Strait off southwestern Japan on Thursday, heading south from the Sea of Japan to the East China Sea.
The strait is an international waterway where foreign ships, including warships, are allowed to navigate.
Chinese and Russian naval vessels were also spotted navigating through the Tsugaru and Osumi straits in the north and south of Japan last month. They were the first simultaneous maneuvers in the waterways.
Ministry officials say they are analyzing the recent activity, which they describe as extraordinary.