Some conservative members of Donald Trump's "Make America Great Again" movement have reacted angrily to the president's plans to sell weapons to Nato, arguing it is a betrayal of his promise to end US involvement in foreign wars.

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.

Ukrainian President Volodymyr Zelenskiy also held talks with a U.S. envoy on Monday on increasing weapons production and arms purchases.