Hours after Russian president Vladimir Putin claimed on Thursday that he had no intention of using nuclear weapons in Ukraine, President Joe Biden expressed skepticism and slammed Putin for what he called “dangerous” brinkmanship.

“I think if he has no intention, why does he keep talking about it? Why does he talk about the ability to use a tactical nuclear weapon?" Biden told NewsNation in an interview late Thursday.

"He’s been very dangerous with how he’s approached this, and he should just get out—he could end this all, get out of Ukraine,” the president continued.

On Thursday, Putin told a gathering of foreign policy experts that it was not in Russia’s interests to use a tactical nuclear weapon.

“We see no need for that. There is no point in that, neither political, nor military,” he said, insisting that Russia had only been responding to Western nuclear “blackmail.”

A great deal of recent international concern has been on Russia’s claims that Ukraine could detonate a “dirty bomb” in an effort to frame Moscow—an allegation dismissed by both Ukraine and Western defense chiefs.

According to the Center for Arms Control and Non-Proliferation, a “dirty bomb” can be broadly defined as a conventional explosive with added radiological material.

In his speech on Thursday, Putin took time to repeat the accusation. “Kyiv is seeking some kind of nuclear incident to inflate a new round of struggle against Russia,” he claimed.

“It’s not for nothing that we said about the ‘dirty bomb’ that Kyiv is creating, we even know where it is being made. I instructed [the defense minister] to call foreign colleagues and warn them about the threat of this provocation,” Putin continued.

When asked about the “dirty bomb” claims earlier this week, Biden said that “Russia would be making an incredibly serious mistake for it to use a tactical nuclear weapon.”

“I’m not guaranteeing you that it’s a false-flag operation yet. I don’t know. But it would be a serious, serious mistake,” he added.

Over the past several weeks, Putin has repeatedly raised the specter of using nuclear weapons in response to any potential threats from the West. In a speech last month announcing the mobilization of hundreds of thousands of troops to fight in Ukraine, Putin said Moscow was prepared to use nuclear weapons if Russia’s “territorial integrity” was threatened, adding that Russia “will certainly use all the means at [its] disposal.”

Russia boasts the largest nuclear arsenal in the world with nearly 6,000 nuclear warheads, with 1,500 of them currently deployed, according to the Stockholm International Peace Research Institute.

Ethen Kim Lieser is a Washington state-based Finance and Tech Editor who has held posts at Google, The Korea Herald, Lincoln Journal Star, AsianWeek, and Arirang TV. Follow or contact him on LinkedIn.

Image: Reuters.