South Korea and the US have underlined close cooperation between the two countries.
This came in a phone call between South Korea's First Vice Foreign Minister Kim Hong-kyun and US Deputy Secretary of State Kurt Campbell, during which the two sides slammed deepening cooperation between North Korea and Russia.
They also expressed deep concern and strong condemnation of North Korea and Russia's conclusion of the comprehensive strategic partnership treaty and their agreement to enhance military and economic cooperation between them.
Campbell expressed his country's strong support for any measures taken by the South Korean side in response to the security threats posed by the illegal military cooperation between Russia and North Korea.
The wo sides agreed to keep close tabs on any potential provocations by the North and maintain a thorough readiness based on strong extended deterrence.
