Russia’s claim that it has fired a new Oreshnik hypersonic missile in combat, and tested a nuclear-capable variant, marks a sharp escalation in the technological arms race unfolding along NATO’s eastern flank.

Russia fired its new Oreshnik intermediate-range ballistic missile at the western Ukrainian city of Lviv overnight on Jan. 9, the Russian Defense Ministry said, calling the attack "retaliation" for an attempted Ukrainian drone strike on one of President Vladimir Putin's residences, a claim Kyiv has denied.

Russia bombarded Ukraine with hundreds of drones and dozens of missiles in a large-scale overnight attack, officials said Friday, killing at least four people in the capital. For only the second time in the nearly four-year-old war,