MOSCOW: Russia moved to ratify a key defense pact with North Korea on Thursday, while South Korea warned it would not “sit idle” if Pyongyang deployed thousands of troops to help Moscow fight Ukraine. Seoul’s spy agency says thousands of North Korean soldiers are currently training in Russia and are likely to deploy to the front lines in Ukraine soon, with thousands more to be sent by December. Lawmakers in Russia’s lower house of parliament voted unanimously on Thursday to ratify a treaty with North Korea that provides for “mutual assistance” if either party faces aggression.

The accord will be now sent to the upper house, the Federation Council, for its approval. Both houses of parliament act as rubber stamps for the Kremlin. The West believes North Korea is already giving Moscow weapons to use in its Ukraine offensive.

“South Korea won’t sit idle over this,” South Korean President Yoon Suk Yeol said of Pyongyang’s reported troop deployments, after talks with visiting Polish President Andrzej Duda. The two countries agreed North Korea’s deployment was “a provocation that threatens global security beyond the Korean Peninsula and Europe,” he added. South Korea, one of the world’s top 10 weapons exporters, has long resisted calls from its allies, including Washington, to supply Kyiv with weapons.

But it has hinted it could review this policy in light of North Korea’s actions and Yoon said Thursday that Seoul would “take necessary actions in coop.