Russian officials threatened the West on Saturday with an uncontrolled escalation of war and Ukraine with the destruction of Kyiv as Western leaders discussed whether to allow Ukraine to use their weapons for strikes deep into Russian territory.

Ukrainian President Volodymyr Zelenskiy said late on Friday that his plan to achieve victory depended on Washington’s decision, a clear reference to the authorisation 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.

While no official decision on the matter has been announced so far, Russian Deputy Foreign Minister Sergei Ryabkov alleged it had already been made and communicated to Kyiv, and that Moscow would have to respond with actions of its own.

“The decision has been made, the carte blanche and all indulgences have been given (to Kyiv), so we are ready for everything,” the RIA news agency quoted Ryabkov as saying. “ And we will react in a way that will not be pretty.”

‘MELTED SPOT’

Former Russian President Dmitry Medvedev, who now serves as deputy chairman of the country's security council, said the West was testing Russia's patience but it was not limitless.

Medvedev said Ukraine's incursion into Russia's Kursk region, which Zelenskiy described as a successful operation slowing Russia's advance, already gave Russia formal grounds to use its nuclear arsenal.

He said that Moscow could either resort to nuclear weapons in the end, or use some of its non-nuclear but still deadly novel weapons for a large-scale attack.

“And that would be it. A giant, grey, melted spot instead of ‘the mother of Russian cities’,” he wrote on the Telegram messaging app, referring to Kyiv.

Ukraine’s Yermak, in turn, said of Russian President Vladimir Putin: “Loud threats of Putin's regime testify only to his fear that terror may come to an end.”