Russian President Vladimir Putin has threatened to strike Ukraine again with a new nuclear-capable ballistic missile following Moscow’s latest widespread attack on critical energy infrastructure.

Ukraine says Russia has launched an intercontinental ballistic missile overnight targeting Dnipro city in the central-east of the country, which, if confirmed, would be the first time Moscow has used such a missile in the war.

There was a cautious note of optimism among some Ukrainians for Gen. Keith Kellogg’s past supportive remarks for Ukraine to defend itself.

Russian President Vladimir Putin threatened on Thursday to fire the military's new medium-range missiles at further targets in Ukraine, including the capital Kiev. The Oreshnik ballistic missile was first deployed last week against the Ukrainian industrial city of Dnipro,

Explosions were reported in Kyiv, Kharkiv, Rivne, Khmelnytskyi, Lutsk, and many other cities in central and western Ukraine.

All regions of Ukraine were under air raid alerts early Thursday amid Russia's latest long-range drone and missile barrage against the country's energy grid, with almost 1 million people reportedly left without power.