Senior Russian security official and former president Dmitry Medvedev said on Saturday Russia could destroy Ukraine's capital Kyiv with non-nuclear weapons in response to the use of Western long-range missiles by Ukraine.
Medvedev said Moscow already had formal grounds to use nuclear weapons since Ukraine's incursion into Russia's Kursk region, but could instead use some of its new weapon technologies to reduce Kyiv to "a giant melted spot" when its patience runs out.
"Holy shit! It's impossible, but it happened," he wrote in English on the Telegram messaging app.
Ukrainian President Volodymyr Zelenskiy said late on Friday that his plan to achieve victory depended on Washington's decision, a clear reference to the authorization for long-range strikes that Kyiv has long sought from NATO allies.
Andriy Yermak, head of Zelenskiy's office, said on the Telegram messaging app on Saturday: "Strong decisions are needed. Terror can be stopped by destroying the military facilities where it originates."
Kyiv has said such strikes are critical for its efforts to restrict Moscow's ability to attack Ukraine, but allies have so far been reluctant to permit them, citing fears Moscow will treat them as an escalation and doubting their efficiency.