US warned Russia to 'stop the loose talk' on nuclear weapons: Blinken

The US has sent private warnings to Russia to "stop the loose talk" regarding nuclear weapons, Secretary of State Antony Blinken said Sunday.

In an interview with “60 Minutes,” an American television news magazine broadcast on the CBS television network, the top US diplomat confirmed reports that Washington privately warned Moscow against using nuclear weapons.

"We have been very clear with the Russians publicly and as well as privately to stop the loose talk about nuclear weapons," Blinken said in New York on the margins of the UN General Assembly.

"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," he said.

"Any use of nuclear weapons would have catastrophic effects for, of course, the country using them, but for many others as well," Blinken added.

CNN reported on Friday that the State Department was involved in conveying the warnings, and the US may have also relied on sensitive intelligence channels to communicate to the Russians.

The report comes after Russian President Vladimir Putin issued a stark warning that he is prepared to use nuclear weapons as he and his proxies prepared to hold polls in separatist-controlled areas of Ukraine.

"When the territorial integrity of our country is threatened, we will certainly use all the means at our disposal to protect Russia and our people. This is not a bluff," Putin said.

The polls, denounced as a "sham" by the US and its allies, began on Friday and are slated to run through Tuesday.

Separatist-controlled Luhansk, as well as Donetsk, Kherson and Zaporizhzhia, which are partly under Russian control, announced plans for the referendums earlier in the week.