Russian lawmaker Maria Butina said on Monday that the administration of President Joe Biden was risking World War Three if it had allowed Ukraine to use US-made weapons to strike deep into Russia.
"These guys, Biden's administration, is trying to escalate the situation to the maximum while they still have power and are still in office," Ms Butina told Reuters.
"I have a great hope that (Donald) Trump will overcome this decision if this has been made because they are seriously risking the start of World War Three which is not in anybody's interest."
Reuters, citing two US officials and a source familiar with the decision, reported on Sunday that Biden's administration has made the decision to allow Ukraine to make the strikes with US weapons deep into Russia.
The New York Times also reported that Joe Biden's administration had made the decision. The Kremlin has yet to comment on the reports.
"The West has decided on such a level of escalation that it could end with the Ukrainian statehood in complete ruins by morning," Andrei Klishas, a senior member of the Federation Council, Russia's upper chamber of parliament, said on the Telegram messaging app.
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.
Russia would be forced to take what Putin called "appropriate decisions" based on the new threats.
Leonid Slutsky, chairman of the State Duma lower house's foreign affairs committee, said that US authorisation of strikes by Kyiv on Russia with US ATACMS tactical missiles would lead to the toughest response, Russian news agencies reported.
"Strikes with US 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.
President Vladimir Putin said on September 12 that Western approval for such a step would mean "the direct involvement of NATO countries, the United States and European countries in the war in Ukraine" because NATO military infrastructure and personnel would have to be involved in the targeting and firing of the missiles.
In late October, Putin said that Russia's defence ministry was working on different ways to respond if the United States and its NATO allies help Ukraine to strike deep into Russia with long-range Western missiles.
"I guess there are some people in the United States who have nothing to lose for whatever reason or who are completely off the grid so much that they simply do not care," said Ms Butina, who spent 15 months in US prison for acting as an unregistered Russian agent and is now a lawmaker for the ruling United Russia party.
Vladimir Putin had also updated its nuclear doctrine to say that if Moscow came under direct attack from the West, Russia may even consider a nuclear response. Joe Biden's decision for allowing Ukraine to use western missiles to target Moscow is a step that risks such a response.
