TAIPEI (Taiwan News) — Japan's Ministry of Defense on Thursday (Sept. 29) announced that seven Chinese and Russian naval vessels had patrolled around the country from Monday (Sept. 26) through Thursday.

According to the ministry, three Chinese warships sailed near the Izu Islands on Monday and four Russian vessels passed near the islands on Tuesday (Sept. 27), reported NHK. The ministry cited the Japanese Maritime Self-Defense Force as stating that the Chinese military vessels linked up with the Russian vessels in waters to the south of Shikoku.

The warships were then tracked moving through the Osumi Strait on Wednesday (Sept. 28) and Thursday. They then reportedly traveled in two columns upon entering the East China Sea.

This marks the second time Chinese and Russian warships have transited the strait together. The previous passage took place in October of 2021.

Among the Chinese vessels was a Renhai-class missile destroyer, which was spotted about 300 kilometers south-southwest of Shionomisaki Cape in Wakayama Prefecture at 9 a.m. on Tuesday, reported The Japan News. The Russian warships included an Udaloy I-class destroyer, which was detected transiting through Japan’s contiguous zone between Mikura Island and Hachijo Island in Tokyo’s Izu Islands chain, that same day at 11 a.m.

General Yamazaki Koji, the chief of Japan's Self-Defense Forces Joint Staff, was cited by NHK as saying that he believes that the Russian and Chinese navies are "cooperating more closely than before." He then stated that Japan's military will "stay vigilant and keep a close watch on developments."

Map shows locations and dates warships were spotted. (Japan Ministry of Defense image)