(NewsNation) — Interviewed on Russian state television, Russian Foreign Minister Sergey Lavrov addressed the escalation of the war in Ukraine and the potential for a nuclear showdown.

Lavrov said the threat of a nuclear conflict “should not be underestimated.”

“I would very much not like that now, when the risks are really very, very significant,” he said. “I would very much not like these risks to be artificially inflated, and there are many who want them. The danger is serious, it is real, it cannot be underestimated.”

Pentagon spokesman John Kirby responded in an interview with CNN, saying, “That kind of rhetoric is clearly not called for in the current scenario.”

“A nuclear war cannot be won and it shouldn’t be fought,” Kirby said. “What is called for is Mr. Putin ending this war.”

Lavrov cautioned that if the Western flow of weapons into Ukraine continues, the talks aimed at ending the fighting will not produce any results.

Lavrov’s statements came as diplomatic efforts to end the fighting continued and U.N. Secretary-General António Guterres met with Russian President Vladimir Putin.

Guterres urged Russia to allow the evacuation of civilians trapped in the steel plant in Mariupol. Putin said Ukrainian troops were using civilians in the plant as shields and not allowing them to leave.

As the war continues to rage in Ukraine, allegations grow of Russian war crimes, the use of banned weapons and the deliberate targeting of civilians.

There are persistent concerns that the conflict will escalate to the use of battlefield nuclear weapons.

A recent NewsNation/Decision Desk HQ poll of 1,021 registered voters found 82% are at least somewhat concerned about a nuclear attack sometime within the next decade.

According to Ohio State National Security Law Professor, Dakota Rudesill, the poll responders have a good cause to worry about.

“I wont mince words, we’re in the worst international security crisis probably since the Cuban missile crisis of 1962,” Rudesill said on Tuesday’s “NewsNation Prime” broadcast.

“The concern here is that Vladimir Putin will become so desperate by the situation in Ukraine in his continuing losses, that he would decide at some point that he’s going to try and escalate the situation by resorting to use of smaller nuclear weapons and try to intimidate Ukraine into surrender,” he said.

According to the professor, the U.S. has played the threat right, telling NewsNation “they paid very close attention to what Vladimir Putin and the rest of the Russian leadership has said in regard to nuclear forces and our terror apparatus is carefully watching them,” he continued.

The U.S. and its allies have promised new packages of heavy weapons for Ukraine, brushing off a threat from Moscow that their support for Kyiv could lead to an escalation on several fronts.

NewsNation contributor Dmitri Alperovitch, tweeted,” I remain convinced — as I have been from day 1 of the war — that the likelihood of Russia executing a nuclear strike is minimal IF we continue to avoid a direct RU-NATO conflict. If we don’t, then yes, all bets are off.”

The U.S. pressed its allies Tuesday to move “heaven and earth” to keep Kyiv well-supplied with weapons.

After his visit to Kyiv, U.S. Secretary of State Antony Blinken noted the United States’ support of Ukraine.

“Ukrainians are standing up, they are standing strong, and they’re doing that with the support that we have coordinated from literally around the world,” Blinken tweeted.

Lavrov took notice, saying, western military support is a choice deliberately raising the stakes.

“Of course, these weapons will be a legitimate target for Russia’s military acting within the context of the special operation,” he said. “How can it be otherwise, if NATO essentially engages in war with Russia through a proxy and is arming that proxy? War means war.”

At the same time, Lavrov stressed that “nuclear war is unacceptable and this is Moscow’s principled position.”

Lavrov also mentioned that the United Nations and its five permanent members — which includes Russia — have made a commitment to the nonproliferation of nuclear weapons.

NewsNation’s “Rush Hour” spoke to retired Marine Col. Mark Cancian on Tuesday, asking if NATO was taking these threats seriously. He says they are.

“Russia has been rattling it’s nuclear saber from the very beginning of the conflict, threatening NATO and trying to keep NATO forces out of Ukraine and conversely, the United States and NATO have told Russia to keep out of NATO territory and I think both side have come to accommodation,” he said.

Cancian, who is also senior adviser with the CSIS International Security Program, went on to say that it’s unlikely Russia would use nuclear forces, explaining that the best time to do so would have been in the beginning when they were initially trying to capture Kyiv.

“Unless we get in a situation where the Russian army maybe collapses and the Ukrainians maybe push into Russia proper, then you can imagine Russians using nuclear weapons. They do have a doctrine of using nuclear weapons to offset conventional weakness,” he said.

The Associated Press contributed to this report.