Zelenskyy has previously accused North Korea of sending troops to Russia's army but this was the first time he gave an exact figure.
Ukraine's foreign minister called North Korean involvement in Russia's war in his country a 'huge threat of escalation'
Mr Zelenskiy went into further detail about support North Korea is reportedly now providing Russia in its war with Ukraine.
Zelensky conducted a whirlwind tour of Western capitals earlier this month including Washington, Paris, Berlin, Rome and London to promote his initiative.