Russian Foreign Minister Sergei Lavrov met North Korean leader Kim Jong Un in the coastal city of Wonsan on Saturday, where he described the two nations’ relations as “an invincible fighting brotherhood”, Russia’s foreign ministry said.

The ministry quoted Lavrov as saying that the visit represented the continuation of “strategic dialogue” between the two sides inaugurated by Russian President Vladimir Putin's visit to North Korea last year.

In a message passed on by Lavrov, Putin said that he hoped for more direct contacts in future, TASS news agency reported.

Lavrov, the ministry said, also thanked North Korea for the troops it had sent to Russia.

Relations between the two countries deepened during the conflict in Ukraine. Thousands of North Korean troops were deployed during the months-long campaign to oust Ukrainian forces from Russia's Kursk region, while Pyongyang has also supplied Russia with munitions.

Lavrov also met with his North Korean counterpart, Choe Son Hui, TASS reported.

Lavrov arrived in Wonsan on Friday from Malaysian capital Kuala Lumpur following the ASEAN foreign ministers' meeting. Home to a newly opened seaside resort, Wonsan is also known for its missile and naval facilities.

Lavrov's visit is the latest high-level meeting between the two countries as they upgrade their strategic cooperation to now include a mutual defence pact.

"We exchanged views on the situation surrounding the Ukrainian crisis ... Our Korean friends confirmed their firm support for all the objectives of the special military operation, as well as for the actions of the Russian leadership and armed forces," TASS quoted Lavrov as saying.

It also quoted his deputy Andrei Rudenko as saying more high-level delegations would visit North Korea later this year.

The South Korean intelligence service has said North Korea may be preparing to deploy more troops in July or August, after sending more than 10,000 soldiers to fight alongside Russia in the war against Ukraine.

North Korea has agreed to dispatch 6,000 military engineers and builders for reconstruction in Russia's Kursk region, where Ukrainian forces launched a mass cross-border incursion nearly a year ago.

Russian news agencies said after North Korea, Lavrov was due to travel to China to attend the Shanghai Cooperation Organisation meeting, scheduled for Monday and Tuesday.

TASS said the new Wonsan coastal resort could boost Russian tourism to North Korea, citing the resumption of direct trains from Moscow to Pyongyang and a project to build a bridge across the Tumen River forming part of the boundary between North Korea, China and Russia.