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.

The drill takes place as the US Air Force is hosting the “Resolute Force Pacific 2025” exercise in various locations including Hawaii, Guam and Japan, as well as international airspace.

The exercise began on July 10 and extends to August 8, and involves more than 400 aircraft and 12,000 personnel from the US and allies such as Japan and Australia.

The US Air Force has described it as their “biggest combat exercise in the region”.

“The US, clinging to its Cold War mentality, has been constantly flexing its muscles in the Asia-Pacific region and attempting to gang up under the guise of ‘military drills’, intimidate and pressure other countries, and undermine peace and stability in the region,” Zhang said.

As Beijing and Moscow have deepened their partnership in recent years, increased joint naval cooperation has become a key component of the strengthening of their military ties.

This will be the 11th exercise in the Joint Sea series, also known as “Maritime Cooperation”. It began in 2012 and has been held annually, except for 2018, 2020 and 2023.

Most of the previous exercises were held in the northwestern Pacific, but they have also been held in the Baltic and Mediterranean seas.

The series involves warships, aircraft, and support units from both sides, conducting operations including formation manoeuvres, search and rescue exercises, air defence drills, anti-submarine operations and live-fire shootings. Demonstrations of interoperability are also part of the exercise.

A similar “Northern Cooperation” exercise, led by the People’s Liberation Army Northern Theatre Command, began in 2023, when there was no Joint Sea exercise, but both events were held last year, with the Joint Sea exercise in July in the South China Sea and the Northern Cooperation drill held in September in the Sea of Japan and the Sea of Okhotsk.

The two navies started joint patrols in the Pacific region in 2021, usually occurring before or after a joint exercise. Such patrols happened twice last year, in July and September, by ships of the PLA Southern Theatre Command and the Northern Theatre Command, respectively. - SOUTH CHINA MORNING POST