The US president spoke to reporters on the White House South Lawn on Tuesday afternoon, the day after he threatened to impose "secondary tariffs" on Moscow

“Putin will not negotiate as a loser,” one of his longtime associates tells TIME by phone from Moscow. “He knows that winners don’t get punished, and if he wins, all of this” — the sanctions, the tariffs — “will go away.”

But his frustration with Putin has grown. Last week, the president said the United States was taking “a lot of bullshit” from Putin. Today, he authorized a significant shipment of U.S. defensive weapons to Ukraine via NATO and threatened Russia with new tariffs if the war does not end in 50 days.

The Kremlin said on Tuesday that U.S. President Donald Trump's recent statements, including a threat of sanctions on buyers of Russian exports, are serious and require analysis.

Vladimir Putin’s conduct has prompted Donald Trump’s shift as Russia’s war effort in Ukraine has gotten only more aggressive.

Trump's threat against Russia runs parallel to a Senate-led effort to pass crippling sanctions on countries that buy Russian energy.

President Trump is hosting NATO Secretary General Mark Rutte at the White House on Monday as the U.S. agrees to sell new and more weapons to Europe and Ukraine.