South Korea vowed Tuesday to take "phased measures" against North Korea and Russia over their deepening military cooperation, and urged North Korea to immediately withdraw its troops from Russia. The presidential National Security Council (NSC) convened a meeting to assess the situation after the National Intelligence Service reported that North Korea has decided to send around 12,000 troops to assist Russia, with approximately 1,500 soldiers already deployed to Russia's Far East. The NSC said the development poses a "significant security threat" to both South Korea and the international community and is a "blatant violation" of U.N. Security Council resolutions prohibiting military cooperation with North Korea. "The government calls for the immediate withdrawal of North Korean troops," deputy national security adviser Kim Tae-hyo said in a briefing. "If the illegal military cooperation between North Korea and Russia continues, (South Korea) will not stand by but respond firmly in collaboration with the i nternational community," Kim said, warning of "phased measures" in response to the level of their military ties. Among the possible scenarios include sending weapons for defense and attack, a senior presidential official told reporters. In June, South Korea indicated the possibility of supplying weapons to Ukraine after North Korean leader Kim Jong-un and Russian President Vladimir Putin signed a pact pledging mutual defense. However, Seoul has so far maintained its stance of providing Ukraine with non-lethal humanitarian aid. Source: Yonhap News Agency