Kim Jong Un has pledged “full support” for Russia’s Putin in his fight against Ukraine. Seoul and Kyiv say he’s now doing that by sending in military personnel.

A Ukrainian military intelligence official, speaking on the condition of anonymity to discuss a sensitive security matter, said “several thousand” North Korean infantry soldiers are undergoing training in Russia now and could be deployed to the front line in Ukraine by the end of this year.

North Korea has likely deployed its troops alongside Russian forces in Ukraine. North Koreans may be assisting with the launch of KN-23 missiles, The Guardian reports. According to the media outlet, North Korean military engineers are likely assisting Russia in launching ballistic missile strikes against Ukraine.