Russia's nuclear rules say it can use atomic weapons if the country — or one of its allies — is attacked, especially if the attacker is a non-nuclear nation backed by a nuclear power. That clause could be seen as applying to Ukraine,

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.

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

Donald Trump’s remarks on Ukraine on Monday were far from the biggest announcement the US president could have made.

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

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

Trump's moves underline his growing disenchantment with Russian President Vladimir Putin over the lack of progress in U.S.-led efforts to secure a ceasefire.

US President Donald Trump has threatened Russia with "very severe" tariffs if there is no cease-fire agreement between Kyiv and Moscow within 50 days and he vowed to supply Ukraine with “billions of dollars” worth of new military hardware in the upcoming days.