Trump on Monday said the United States would ship "billions of dollars' worth" of military equipment to NATO members, paid for by the alliance, to be handed over to Ukrainian forces battling grinding Russian advances. Trump had earlier this month suggested NATO would "100 percent" pay for U.S. weapons, which would be sent to Ukraine.

Trump said the United States would put secondary tariffs on countries that do business with Russia if a peace deal is not reached in 50 days.

U.S. President Donald Trump's decision to ramp up arms shipments to Ukraine is a signal to Kyiv to abandon peace efforts, Russia said on Thursday, vowing it would not accept the "blackmail" of Washington's new sanctions ultimatum.