Russian President Vladimir Putin on Wednesday thanked North Korean leader Kim Jong Un for sending troops to repel Ukraine's incursion in Kursk as the pair sat down for talks in Beijing.

The two leaders met formally at the Diaoyutai state guest house after attending a major military parade in the heart of the Chinese capital that marked the 80th anniversary of the end of World War II.

Putin and Kim traveled from a formal reception to the negotiations in the same car, the Kremlin said in a post on social media.

Speaking in front of journalists as the meeting began, Putin praised North Korean troops who "fought bravely and heroically" alongside Moscow’s forces to repel Ukraine's incursion into Russia’s Kursk border region.

According to South Korean assessments, North Korea has sent around 15,000 troops to Russia since last year.

It has also sent large quantities of military equipment, including ballistic missiles and artillery, to help fuel Putin’s three-year invasion of Ukraine.

"As is well known, on your initiative, your special forces took part in liberating Kursk region in full accordance with our new agreement," Putin acknowledged.

He commended the cooperation between both Moscow and Pyongyang, saying "lately our relations have taken on a special, trustworthy, friendly and allied character."

The anniversary celebrations in Beijing mark the first time that Kim has attended a major multilateral event during his 14-year rule, and the first time Kim, Putin, and Chinese leader Xi Jinping, have gathered at the same venue.

Observers are waiting to see if Kim possibly meets Xi bilaterally as well, or even holds a private trilateral meeting with Xi and Putin, although none of the three countries have confirmed such an event.