The United State’s decision to lift the missile ban from Ukraine and allow Kyiv to strike into Russia with long-range U.S. missile has created uproar in the country.

Senior Russian lawmakers said on Sunday that the missiles ould escalate the conflict in Ukraine and could lead to World War Three.

Andrei Klishas, a senior member of the Federation Council, Russia’s upper chamber of parliament, said on the Telegram messaging app: “The West has decided on such a level of escalation that it could end with the Ukrainian statehood in complete ruins by morning.”

Vladimir Dzhabarov, first deputy head of the Russian upper house’s international affairs committee, said that Moscow’s response will be immediate.

“This is a very big step towards the start of World War Three,” the TASS state news agency quoted Dzhabarov as saying.

President Vladimir Putin said in September that the West would be fighting Russia directly if it allowed Ukraine to strike Russian territory with Western-made long-range missiles, a move he said would alter the nature and scope of the conflict, reports Reuters.

Leonid Slutsky, chairman of the State Duma lower house’s foreign affairs committee, said that U.S. authorisation of strikes by Kyiv on Russia with U.S. ATACMS tactical missiles would lead to the toughest response, Russian news agencies reported.

“Strikes with U.S. missiles deep into Russian regions will inevitably entail a serious escalation, which threatens to lead to much more serious consequences,” TASS news agency quoted Slutsky as saying.