The Kremlin said U.S. President Donald Trump has not yet responded to Russian President Vladimir Putin's offer to extend the New START treaty, which limits strategic nuclear weapons and is due to expire in February.

The hypersonic Oreshnik intermediate range ballistic missile hit Ukraine's western Lviv region late Thursday night, although officials there did not mention any casualties.

The Russian military used its cutting-edge Oreshnik hypersonic ballistic missile system last week to strike a Ukrainian aviation plant in Lviv, which was servicing F-16s and MiG-2

The death of the last treaty between Russia and the U.S. that limited the size of nuclear arsenals may spark a new arms race, says a former security council director.

Russia fired a hypersonic Oreshnik missile at a target in western Ukraine overnight Thursday, near the border with NATO member Poland, in what has been labeled a brazen “warning” to the wider continent and the United States.

IAEA Director General Rafael Grossi says the use of nuclear weapons in the Russia-Ukraine war is "unlikely", while Iran holds uranium enriched to 60 percent, cautioning against any move to exit Nuclear Non-Proliferation Treaty.

WASHINGTON — The U.S. government publicly warned that Russia might seek to use chemical or biological weapons in Ukraine, after Russia, without evidence, accused Ukraine of having chemical weapons labs. White House press secretary Jen Psaki called Russia ...