Russia's President Vladimir Putin, right, and China's President Xi Jinping attend the opening ceremony for the Naval Cooperation 2014 joint exercises at a command center of the Wusong naval base in Shanghai. Russia and China have taken turns hosting the exercises, dubbed "Joint Sea", since 2012.

A Chinese naval fleet is steaming towards the Baltic Sea to participate in joint exercises with Russia, with the show of force to take place after US President Donald Trump visits NATO ally Poland next month.

The three ships, headed by the Changsha destroyer, will link up with Russian vessels for drills near St Petersburg and Kaliningrad, Chinese state media reported.

Russia and China have taken turns hosting the exercises, dubbed "Joint Sea", since 2012.

This year's iteration is set to take place in late July, Xinhua news agency said, and will include Chinese marines and ship-borne helicopters.

Trump is expected to visit Poland, which is on the Baltic Sea, on July 5-6 ahead of his participation in the G20 summit in Germany.

The US president has taken a tough stance on the alliance, which has been a perpetual thorn in Russia's side, leaving many to question his commitment to the joint-security arrangement that was born during the Cold War.

Xinhua said late Sunday that this year's drills aim "to consolidate and advance the Sino-Russian comprehensive strategic partnership of coordination, and deepen friendly and practical cooperation between the two militaries."

The exercises, it added, will also "improve coordination between the two navies on joint defence operations at sea".

Previous year's drills have also been held in politically sensitive areas.

Last year, the exercises took place in the contested South China Sea, where Beijing's construction of artificial islands in waters claimed by its neighbours has drawn criticism from the US and other nations which say the project threatens freedom of navigation through the region.