Ukrainian president Volodymyr Zelensky North Korea is preparing to send 10,000 troops to aid Russia’s war against Ukraine, in a sign of deepening military cooperation between Moscow and Pyongyang.

“We know about 10,000 North Korean soldiers that they want to send to fight against us,” Zelenskiy told reporters in Brussels on Thursday. Ukrainian officials have said for weeks that North Korean soldiers were fighting in Ukraine, without providing evidence.