President Donald Trump is threatening to impose stiff taxes, tariffs and sanctions on Russia if an agreement isn’t reached to end the war in Ukraine.

President Trump has demanded Russia stop its “ridiculous war” with Ukraine or face stiffer penalties — but the U.S. doesn’t appear to have much financial leverage left after a raft of prior sanctions.

Ukrainian diplomacy on Wednesday, threatening Moscow with sanctions and calling on President Vladimir Putin to make a deal for the sake of his economy.