President Trump now wants to give more weapons to Ukraine and is threatening increased sanctions if Russian President Vladimir Putin doesn't agree to end the war in 50 days. The president explained why in a phone call with our partners at BBC News.

It remains to be seen just how lasting and severe President Donald Trump’s turn against Vladimir Putin will be. Trump has criticized the Russian president in unprecedented terms in recent days and signaled he’ll send vital weapons to Ukraine.

President Donald Trump’s new weapons deal and his increasing criticism of Vladimir Putin have sparked fear among some Russians that Putin could overplay his hand.

“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.”

Russia assaulted Ukraine with a fresh wave of deadly drone and missile strikes Wednesday in another audacious rebellion of President Trump’s 50-day peace ultimatum to Vladimir Putin. Northeastern

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

I’m disappointed in President Putin, because I thought we would have had a deal two months ago,” President Trump said.

U.S. President Donald Trump repeatedly said during his campaign he would be able to end the war between Russia and Ukraine “in 24 hours” upon taking office.