WASHINGTON (Reuters) – The U.S. Department of Defense said on Monday that it continued to see unusual military activity and a concentration of Russian forces near its border with Ukraine.

Pentagon spokesman John Kirby said the build-up was concerning and U.S. Defense Secretary Lloyd Austin would meet his Ukrainian counterpart on Thursday.

Kirby declined to speculate about the purpose of the Russian military movements and did not offer further details.

(Reporting by Phil Stewart and Idrees Ali, Editing by Rosalba O’Brien)