China's top diplomat Wang Yi will begin a four-day visit to Russia for security talks on Monday, his foreign ministry said, the latest in a series of high-level visits and phone calls between the two sides.

China and Russia are strategic allies, with both countries frequently touting their "no limits" partnership and economic and military cooperation.

Their ties became even closer after Russia invaded Ukraine in February last year, which China has refused to criticize.

China's foreign ministry said in a statement Monday that Wang "will go to Russia to hold the 18th round of the China-Russian Strategic Security Consultations (SSCC) from 18 to 21 September" at the invitation of Nikolai Patrushev, secretary of Moscow's security council.

In an earlier briefing, the Russian foreign ministry said Wang would meet with his counterpart Sergei Lavrov, and the two planned to "focus on efforts to strengthen collaboration on the international scene".

"There will be a detailed exchange of views on issues related to a settlement in Ukraine, as well as ways of ensuring stability and security in the Asia-Pacific region," a spokesperson said.

China has sought to position itself as a neutral party in the Ukraine war while offering Moscow a vital diplomatic and financial lifeline as its international isolation deepens.

But it has stopped short of overt military involvement or sending lethal arms to Moscow.

Last month, Chinese Defence Minister Li Shangfu visited Russia and Belarus and called for closer military cooperation.

In recent months the two countries have carried out joint sea and air patrols, the latter of which caused South Korea to deploy fighter jets as a precaution.

The high-level contact looks set to ramp up, with an aide to Vladimir Putin saying in July that the Russian president was planning to visit China in October.

In March, President Xi Jinping made a state visit to Moscow and declared relations between the two countries were entering a new era.