Seven Chinese naval vessels passed an international strait off Kyushu, southwestern Japan, Japan's Defense Ministry said Wednesday.
The seven ships -- four destroyers, two guided missile frigates and a support ship -- were seen sailing north through the Tsushima Strait off Nagasaki Prefecture and between Japan and South Korea, early Wednesday, a ministry official said.
Passage through the Tsushima Strait, a high seas corridor, does not pose a problem under international law, even for warships.
Chinese naval vessels were last seen sailing through the strait in August 2011, according to the ministry.
According to China's Xinhua News Agency, a fleet of seven naval vessels departed from Qingdao harbor in eastern China on Monday to take part in joint naval drills with Russia in the Sea of Japan, apparently coinciding with the seven ships seen passing through the Tsushima Strait.