WASHINGTON (AP) — The White House said on Friday that North Korea has delivered more than 1,000 containers of military equipment and munitions to Russia for its ongoing war in Ukraine.

Speculation about a possible North Korean plan to refill Russia’s munition stores drained in its protracted war with Ukraine flared last month, when North Korean leader Kim Jong Un traveled to Russia to meet President Vladimir Putin and visit key military sites.

White House National Security Council spokesman John Kirby said that the U.S. believes Kim is seeking sophisticated Russian weapons technologies in return for the munitions to boost North Korea's nuclear program.