Russian officials and commentators have shown little indication that Moscow is about to change course under new pressure.

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.

Senate Majority Leader John Thune discusses efforts to pass a rescissions package, the Epstein files and the Trump administration's Ukraine policy on 'Special Report.'

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

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

U.S. President Donald Trump said he was disappointed but not done with Russian President Vladimir Putin, according to a BBC interview published on Tuesday, hours after Trump announced new weapons for Ukraine and threatened Russia with sanctions.

President Donald Trump said he will hit the Russian economy hard if Russia does not agree to a ceasefire and, in a policy shift, Trump endorsed a plan to arm Ukraine.