The involvement of North Korean regular troops to support Russia’s invasion of Ukraine would be a serious escalation of the war, France and Ukraine’s foreign ministers said at a joint press conference in Kyiv on Saturday.

France’s Jean-Noel Barrot, who was making his first trip to Ukraine since becoming foreign minister in September, is also set to visit the east of the country, where France will finance new two new centers for the protection of children affected by the war, on Sunday.

Ukrainian President Volodymyr Zelenskyy accused North Korea on Thursday of deploying officers alongside Russia and of preparing to send 10,000 soldiers to help Moscow’s war effort, although NATO chief Mark Rutte said there was no evidence of Pyongyang’s presence at this stage.

“It would be serious and push the conflict into a new stage, an additional escalatory stage,” Barrot said in Kyiv, adding that such a move would signal that Moscow was struggling in the war.

His Ukrainian counterpart, Andrii Sybiha, said the risk of escalation from the move was “huge.”

“This is a huge threat of further escalation of Russian aggression against Ukraine. There is a big risk of it growing out of its current scale and borders,” he said.

Earlier this week, Zelenskyy presented his victory plan, which he said would enable Ukraine to end the war no later than next year. The first step of this plan was unconditional NATO membership for Ukraine.

France’s foreign minister said that Paris was open to the idea of an immediate invitation for Ukraine to join NATO, but that talks would continue on the subject with allies.

“Regarding the invitation for Ukraine to join NATO, we are open to it and it’s a discussion that we are having with our partners,” Barrot said.