South Korea has called in Russian diplomats to lodge complaints over Moscow's criticism of President Yoon Suk Yeol for remarks about North Korea's pursuit of a nuclear arsenal, the foreign ministry said.
Chung Byung-won, South Korea's deputy foreign minister for political affairs, summoned Ambassador Georgy Zinoviev on Saturday to say that Moscow lashing out at Yoon's remarks would only have a negative impact on the relationship between the two countries, the ministry said.
"Deputy Minister Chung said it was very regrettable that Russia ignored the truth and unconditionally protected North Korea while criticising the leader's remarks in extremely rude language, and emphasised that this would only worsen Korea-Russia relations," the ministry said in a statement.
Russian President Vladimir Putin has deepened ties with Seoul's rival, North Korea, since invading Ukraine in 2022. The United States and its allies have condemned what they say have been significant North Korean missile deliveries to Russia to help its war effort.
Yoon told a meeting on Wednesday of defence and security officials: "The North Korean regime is going through fire and water solely for the sake of maintaining its hereditary totalitarian regime, while blatantly ignoring international law and UN Security Council resolutions by trading arms with Russia."
The next day Russian foreign ministry spokeswoman Maria Zakharova called Yoon's remarks "blatantly biased".
She told reporters the comments "look particularly odious", given rising tensions on the Korean peninsula, "primarily due to the brazen policy of the United States and its allies, including (South) Korea and Japan".
Seoul's foreign ministry said on Sunday that Chung had met on Friday with Russia's visiting Deputy Foreign Minister Andrei Rudenko and conveyed Seoul's stern stance on the military cooperation between Pyongyang and Moscow. Kim Gunn, Seoul's nuclear envoy, also met with Rudenko, the ministry said.
The statement said Chung and Rudenko also discussed issues including Russia's war in Ukraine.
Russia's foreign ministry said on Sunday that "an exchange of views" had taken during Rudenko's meetings in Seoul with Chung and other officials.
"The Russian side has expressed serious concerns regarding the sharp escalation of tensions in the subregion," it said in a statement.
"It was clearly stated that its main source is the irresponsible provocative policy of Washington, which, for its own geopolitical purposes, is trying to encourage regional allies to implement their aggressive plans, fraught with unpredictable consequences, including in the military sphere."