SEOUL, South Korea (AP) — Russian President Vladimir Putin met with North Korea’s foreign minister and thanked Pyongyang for supporting his war against Ukraine, in the latest high-level diplomacy between the countries, Russian state media reported.

The visit by North Korean Foreign Minister Choe Son Hui comes without an obvious occasion, such as a multilateral diplomatic event or state anniversary, and has raised speculation that she may be coordinating a possible visit to Russia by North Korean leader Kim Jong Un. North Korean state media said Choe departed for Russia on Saturday at the invitation of Russian Foreign Minister Sergey Lavrov but has yet to comment on the purpose of her visit.

Yoon Min Ho, spokesperson for South Korea’s Unification Ministry, which handles affairs related to North Korea, said Monday that Seoul was closely monitoring the meetings but declined to assess whether Moscow and Pyongyang were discussing another summit between their leaders.

Russia’s Tass news agency said Putin during his meeting with Choe at the Kremlin on Sunday praised the countries’ bilateral relations and reiterated his “gratitude to the North Korean leadership and people” for supporting his military operations against Ukraine. Choe told Putin that Kim remains committed to the “comprehensive development” of relations with Russia, Tass said.

Kim traveled to Russia’s Far East for summits with Putin in 2019 and 2023. Putin invited Kim to visit Russia again during their summit in Pyongyang in June 2024, where the leaders signed a strategic partnership agreement pledging mutual aid if either country faces aggression.

Kim in recent years has made Russia the priority of his foreign policy, sending thousands of troops and huge supplies of weapons to support Putin’s war in Ukraine, possibly in exchange for economic aid and technology transfers that some experts say are helping advance North Korea’s military capabilities.

Kim has also been seeking stronger ties with China, including hosting Chinese President Xi Jinping for a June summit in Pyongyang, as he embraces the idea of a “new Cold War” and projecting Pyongyang as part of a united front against Washington.

Choe’s visit to Moscow came shortly after North Korea and China exchanged high-level visits, with North Korean Cabinet premier, Pak Thae Song, Kim’s top economic official, meeting Xi in Beijing and Wang Huning, a member of the Chinese Communist Party’s powerful Politburo Standing Committee, visiting Kim in Pyongyang this month.

Kim has suspended all meaningful dialogue with the United States and South Korea since the collapse of his nuclear diplomacy with U.S. President Donald Trump in 2019. He has used Russia’s war on Ukraine as a distraction to accelerate the advancement of his nuclear weapons and missile program, while demanding that Washington abandon its calls for North Korea’s nuclear disarmament as a precondition for talks.