South Korean President Yoon Seok-yeol said that military cooperation between North Korea and Russia is an illegal and unusual act that violates United Nations Security Council resolutions and several other international sanctions.
Yoon made these statements in a written interview with a foreign media outlet published on Sunday, one day before he headed to New York in the United States to attend the United Nations General Assembly.
South Korean's remarks came amid fears of deepening military cooperation between Pyongyang and Moscow after a summit between North Korean leader Kim Jong-un and Russian President Vladimir. Putin last Wednesday.
He stressed that the international community must unite more strongly in response to such a move by North Korea and Russia.
Yoon also warned that North Korea would face the "end of the regime" if it tried to use nuclear weapons.