Officers and soldiers from both China and Russia attend the send-off ceremony at the Pier of Golden Horn Bay in Russia, on July 12, 2013. Seven Chinese warships left Russia's far eastern port of Vladivostok Friday morning after taking part in a joint naval drill with Russia.

According to the Japanese defence ministry, a Chinese naval fleet was on Sunday spotted sailing for the first time through an international strait between northern Japan and Russia's far east.

The two missile destroyers, two frigates and a supply ship passed through the Soya Strait from the Sea of Japan to the Sea of Okhotsk early on Sunday, the ministry said.

The five vessels apparently participated in joint naval exercises with Russia from July 5-12 off Vladivostok, but it is unclear why they were passing through that particular area, according to an official from the ministry. [Photo/Xinhua]