South Korea on Friday summoned the Russian ambassador to lodge a protest over a new Russia-North Korea treaty that calls for immediate military assistance if either country is attacked, Yonhap news reported.
First Vice Foreign Minister Kim Hong-kyun called in Russian Ambassador Georgy Zinoviev to deliver Seoul's position on the "comprehensive strategic partnership" treaty signed at a summit between Russian President Vladimir Putin and North Korean leader Kim Jong-un in Pyongyang on Wednesday.
South Korea's presidential office condemned the pact as a threat to national security in violation of UN Security Council resolutions, warning of a negative impact on its relations with Moscow.
Seoul also said it will reconsider its stance on the arms supply to Ukraine. South Korea has so far maintained a policy of only providing non-lethal aid to Kyiv.
Putin, on a state visit to Vietnam, warned that it would be a "very big mistake" if South Korea provided lethal weapons to Ukraine.