As the UN marks the International Day for the Total Elimination of Nuclear Weapons, the United States has warned Russia of "catastrophic" consequences if it uses nuclear weapons as part of the Ukraine invasion.
In a speech on Wednesday announcing the mobilisation of reservists following Ukrainian gains on the ground, Russian President Vladimir Putin made a thinly veiled threat to use nuclear arms in the Ukraine war.
US Secretary of State Antony Blinken confirmed in an interview on Sunday that the United States has already sent several warnings to Russia.
Blinken told the CBS News program "60 Minutes" on the side lines of the UN General Assembly in New York: "We have been very clear with the Russians publicly, and, as well as privately, to stop the loose talk about nuclear weapons."
"It's very important that Moscow hear from us and know from us that the consequences would be horrific. And we've made that very clear," Blinken said.
"Any use of nuclear weapons would have catastrophic effects for, of course, the country using them, but for many others as well."
Decisive response to nuclear threat
In a separate interview, President Joe Biden's national security advisor, Jake Sullivan, said that the United States has warned Russia at "very high levels" of "catastrophic consequences" for using nuclear arms.
The United States and its allies would "respond decisively," Sullivan said on CBS's "Face the Nation."
"We have been clear and specific about what that will entail."
Russia and the United States are the world's largest nuclear weapons powers, but separate from the threats of planetary destruction, Russian military doctrine permits the use of tactical nuclear weapons on the battlefield to force an enemy to retreat.
When asked during a news conference at the United Nations about Putin's comments, Russian Foreign Minister Sergei Lavrov said only that Moscow's doctrine "is an open document."
- Macron asks Putin to withdraw weapons from Ukraine nuclear plant
- UN chief Guterres warns of nuclear horror on 77th anniversary of Hiroshima attack
'Scare the whole world'
Meanwhile, Ukraine's President Volodymyr Zelensky also told "Face the Nation" that Putin's veiled nuclear threat "could be a reality," saying Russian military activity at nuclear power plants in Ukraine are "the first steps of his nuclear blackmail."
"He wants to scare the whole world," Zelensky said of Putin.
"I don't think he's bluffing. I think the world is deterring it and containing this threat. We need to keep putting pressure on him and not allow him to continue," Zelensky added.
UN marks anti-nuclear day
No country has used nuclear weapons on the battlefield except the United States in 1945, when it destroyed the Japanese cities of Hiroshima and Nagasaki, killing more than 200,000 people.
Imperial Japan surrendered days later, ending World War II.
The latest positioning of the nuclear threat at the centre of world politics comes as the United Nations marks the International Day for the Total Elimination of Nuclear Weapons.
In a statement, UN Secretary General Antonio Guterres said the UN rejects claims that nuclear disarmament is some "impossible utopian dream."
"Eliminating these devices of death is not only possible, it is necessary," he said, especially at a "moment of rising geopolitical division, mistrust and outright aggression.
"We are in danger of forgetting the terrible lessons of Hiroshima, Nagasaki and the Cold War, and inciting a humanitarian Armageddon."
Last month, signatories to the Treaty on the Non-Proliferation of Nuclear Weapons reportedly came close to consensus but failed to agree on the total elimination of nuclear weapons.
The UN statement adds "We urge all States to use every avenue of dialogue, diplomacy and negotiation to ease tensions and reduce risk."