North Korea has sent about 10,000 troops to Russia to train and fight in Ukraine within “the next several weeks,” the Pentagon said Monday, in a move that Western leaders say will intensify the almost three-year war and jolt relations in the Indo-Pacific region.

Some of the North Korean soldiers have already moved closer to Ukraine, Pentagon spokeswoman Sabrina Singh said, and were believed to be heading for the Kursk border region, where Russia has been struggling to push back a Ukrainian incursion.