China and Russia announced they oppose the possible deployment of an advanced American missile-defense system in South Korea.
With tensions rising over North Korean nuclear threats, Washington and Seoul last week began talks on deploying the sophisticated THAAD system.
Chinese Foreign Minister Wang Yi said after meeting with Russian counterpart Sergey Lavrov in Moscow on March 11 that putting the system in South Korea would "harm the strategic security interests of China and Russia" and "possibly lead to a new arms race."
Lavrov said deploying the system would be an overreaction.
"The plans, which the U.S. has been nursing together with the Republic of Korea, exceed any conceivable threats that may come from North Korea, even taking Pyongyang's current actions into account," he said.
U.S. State Department spokesman John Kirby said the possible deployment was prompted by North Korea's provocative behavior.
"I don't know if it's going to get deployed, but if it does, there's no reason for the Russians or the Chinese to be concerned about it because it is purely defensive in nature," Kirby said.
Based on reporting by AP, Reuters, and Interfax