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.

Russia has rejected President Trump’s “ultimatum” for Moscow to sign a ceasefire deal to end the war in Ukraine within 50 days on Tuesday as “unacceptable,” calling for continued negotiations and insisting that the invasion ordered by President Vladimir Putin would continue until its goals are achieved.

Pentagon officials said details were still being worked out, and experts doubted Mr. Trump’s threat of huge tariffs for Russian trading partners.

President Trump has effectively handed Vladimir Putin an extraordinary green light: 50 days to finish off his brutal summer offensive in Ukraine before facing any consequences.

Latest news and live updates as Trump announces the U.S. will send Patriot missiles to Ukraine and meets with NATO's secretary general.

Ivo Daalder, a senior fellow at Harvard Belfer Center, says that President Donald Trump realizes that he needs to change course because the Russian leader has been playing him "for years."

U.S. President Donald Trump's Ukraine envoy Keith Kellogg began talks in Kyiv on Monday on security and sanctions against Russia. That's a day after the U.S. president said he would send Patriot air defence missiles to Ukraine.

During his campaign, Trump said bringing a quick end to the war was a top priority and that helping Ukraine was a waste of US taxpayer money.