Western allies of Ukraine have condemned Russia's plans to amend its nuclear deterrence doctrine, in a manner which might consider a "massive" aerial attack on Russia supported by a nuclear state as a "joint attack," even if the attacker is a non-nuclear state.

The update was proposed on Wednesday by President Vladimir Putin, who has the right to pass it. It is seen as a clear reference to Ukraine, as Kyiv presses its Western allies to grant it permission to use the long-range weapons they provide to strike deep within Russia.

Putin gave the example of Russia receiving "reliable information of a massive launch of air and space attack weapons and their crossing our state border," as a case where Russia might consider nuclear retaliation.

How did the West react?

US Secretary of State Antony Blinken criticized the proposed amendment on the sidelines of the UN General Assembly on Thursday.

"It's totally irresponsible, and I think many in the world have spoken clearly about that when he's been rattling the nuclear saber, including China in the past," Blinken said in an interview with MSNBC.

European Union foreign policy spokesman Peter Stano also rejected the plan as "reckless and irresponsible."

"Not for the first time, Putin is playing [a] gamble with his nuclear arsenal," Stano told reporters. "We of course strongly reject these threats."

Kyiv also strongly rejected Putin's proposal.

"Russia has nothing left but nuclear blackmail; it has no other instruments to intimidate the world," Andriy Yermak, head of the president's office, wrote on Telegram on Wednesday evening.

He said attempts to spread fear would not work.

Moscow doubles down on plans

The Kremlin meanwhile doubled down on Putin's amendment on Thursday, with spokesman Dmitry Peskov describing it as a "warning signal" to the West.

"A signal that warns these countries of the consequences if they participate in an attack on our country by various means, not necessarily nuclear," Peskov told reporters.

Without mentioning Ukraine by name, Peskov said Russia's "nuclear deterrence is being adjusted on account of elements of tension that are developing along the perimeter of our borders".

He also said there was "no question" of Moscow boosting its nuclear arsenal, already the world's largest.

Russian officials have warned Western states of the possibility of nuclear war in the event of a direct confrontation.

Putin's announcement came on the same day Ukrainian President Volodymyr Zelenskyy addressed the UN General Assembly in New York, with Kyiv reiterating its demand for permission to use Western weapons to strike deep into Russia.

Moscow's current nuclear doctrine was set out in a 2020 Putin decree. It stipulates that Russia may use nuclear weapons in case of a nuclear attack by an enemy or a conventional attack that threatens the existence of the state.

rmt/msh (AFP, AP, dpa, Reuters)