Russian Deputy Foreign Minister Sergei Ryabkov said on Friday that Moscow was not threatening anybody with nuclear weapons, and that open confrontation with the United States and NATO was not in Russia's interests, state news agencies reported.
"We are not threatening anyone with nuclear weapons," the Interfax agency quoted Ryabkov as saying at a conference on Friday. "The criteria for their use are outlined in Russia's military doctrine."
President Vladimir Putin this week told the West he was "not bluffing" when he said would use nuclear weapons if Russia's territorial integrity was threatened.
Four Russian-controlled regions in Ukraine are staging referendums this weekend on whether to join Russia. Putin has said he supports the move, which has raised the prospect of Russia formally annexing another 15% of Ukraine's territory.
Russian officials, including ex-president Dmitry Medvedev, said that, after the regions are incorporated into Russia, any attack on them by Ukrainian forces would be considered an attack on Russia.
Under Russia's nuclear doctrine, this could permit the use of nuclear weapons if Moscow feels it faces as "existential threat". Medvedev said it had the option of using strategic - long-range - nuclear weapons.
But Ryabkov said Russia was not seeking "open confrontation" with the United States or the NATO military alliance and did not want the situation to escalate further.
"We hope the Biden administration is also aware of the danger of an uncontrolled escalation of the conflict in Ukraine," he was quoted as saying.
Announcing Russia's first mobilisation since World War Two on Wednesday, Putin said Russia was fighting against not only Ukraine, but the entire military resources of the Western countries that back Kyiv.
Also speaking on Friday, Russia's ambassador to the United States, Anatoly Antonov, said he wanted to believe "that despite all difficulties, Moscow and Washington are not on the verge of a collapse into the abyss of a nuclear conflict", the RIA Novosti news agency reported.
(Reporting by Reuters; Editing by Kevin Liffey)
