Some 8,000 North Korean soldiers are now in Russia near Ukraine’s border and are preparing to help the Kremlin fight against Ukrainian troops in the coming days, the Biden administration said Thursday.

The new figure from is a dramatic increase from a day earlier, when Defense Secretary Lloyd Austin would only say “some” of the troops had moved toward Ukraine’s border in the Kursk region, where Moscow’s forces have struggled to push back a Ukrainian incursion

That also would mean most of the North Korean troops that the U.S. and its allies say have been sent to Russia are now on the Russia-Ukraine border.

The U.S. has estimated there are about 10,000 North Korean troops in Russia. Seoul and its allies assess that the number has increased to 11,000, while Ukraine has put the figure higher, at up to 12,000.

Of the 8,000 in Kursk, “we’ve not yet seen these troops deploy into combat against Ukrainian forces but we would expect that to happen in the coming days,” Blinken said at a news conference with Defense Secretary Lloyd Austin and their South Korean counterparts.