Chinese warships have sailed into the main port of Russia’s Pacific Fleet ahead of a joint naval exercise this week in the Sea of Japan – also known as the East Sea, according to Russian media.

The guided-missile destroyers the Shaoxing and the Urumqi arrived at the eastern port city of Vladivostok for the five-day joint naval drill that starts on Friday, state news agency Sputnik reported on Thursday, quoting Russia’s Pacific Fleet.

The drills will also involve diesel-electric submarines and naval aircraft from both countries, according to Russia’s Tass news agency.

The “Joint Sea 2025” drill would be followed by the sixth joint maritime patrol in the Pacific, China’s defence ministry said on Wednesday.

The exercise will take place in the sea and airspace near Vladivostok, Russia’s far eastern port city. Some of the forces in the exercise will then take part in the subsequent joint patrol in designated ocean areas, according to ministry spokesman Zhang Xiaogang.

“This is an arrangement within the annual cooperation plan between the Chinese and Russian militaries. It is not targeted at any third party, nor is it related to the current international and regional situation,” Zhang said in Beijing.

He did not specify the dates of the drill or the size of the event.