NATO will not be cowed by Russian threats but keep up its strong support of Kyiv, NATO Secretary-General Mark Rutte said on his first visit to the alliance's Ukraine mission in Wiesbaden, set to take over the coordination of military aid from the United States.

"The message (to Russian President Vladimir Putin) is that we will continue, that we will do what's necessary to make sure that he will not get his way, that Ukraine will prevail," he told Reuters in a joint interview with German public radio Hessischer Rundfunk on Monday.

Rutte spoke at Clay Barracks, the U.S. base hosting the headquarters of the new mission, dubbed NATO Security Assistance and Training for Ukraine (NSATU), which will gradually assume the coordination of Western military aid to Kyiv.