President Donald Trump on Friday threatened a 100% tax on imports from any country that imposes a tax on digital services from United States companies.
Russia's Foreign Ministry again warned that Moscow will not accept the presence of any Western troops in Ukraine as part of a future peace deal.
On Saturday, multiple postal services around Europe announced that they are suspending the shipment of many packages to the United States amid a lack of clarity over new import duties.
Russian President Vladimir Putin's continued refusal to accept a ceasefire is "complicating" efforts to reach a peace deal, Ukrainian President Volodymyr Zelenskyy said.
British Prime Minister Keir Starmer is meeting Monday with Trump at a golf property owned by the president's family near Turnberry in southwestern Scotland.
Trump has said new tariffs could impact "all countries."