U.S. President Donald Trump threatened to impose stiff financial penalties on Russia if it does not end hostilities with Ukraine even as he pledged fresh weapons supplies for Kyiv.

"We’re going to be doing very severe tariffs if we don’t have a deal in 50 days, tariffs at about 100%,” Trump said Monday during a meeting with NATO Secretary General Mark Rutte at the White House.

Trump said the levies would come in the form of "secondary tariffs,” without providing details. The U.S. president has used the term in the past to describe duties imposed on countries for trading with American adversaries.