Russian President Vladimir Putin on Thursday announced a new nuclear arsenal that included a cruise missile, but experts said that the weapon was not operational and that it had crashed during testing in the Arctic.
"If we're talking about nuclear-armed cruise missiles, that's a technological breakthrough and a gigantic achievement," Aleksandr Golts, an independent Russian military analyst, told The New York Times.
But, he added, "The question is, is this true?"
Golts was among many experts and analysts who voiced suspicions that Putin might be bluffing.
If not, he told the Times, then "these weapons are definitely new, absolutely new."
The cruise missile was among five weapons Putin announced in a state-of-the-nation speech in Moscow.
He displayed each in a video mock-up on giant screens flanking him onstage.
Putin threatened to use the weapons, as well as Russia's older-generation nuclear arsenal, against the United States and Europe if Russia were attacked.
"We would consider any use of nuclear weapons against Russia or its allies to be a nuclear attack on our country," the Kremlin leader said.
He added that he could not show the actual weapons publicly, but assured those political and cultural figures who attended the speech that they had been developed.
Still, other experts said that Putin's rhetoric harkened back to the days of the Cold War, only now that the talk is not "based on greater numbers of bombs but increased capabilities, stealth and guile," the Times reports.
"The real surprise in among all of this is a nuclear-powered cruise missile," said Douglas Barrie, a senior fellow for military aerospace at the International Institute for Strategic Studies in London.
"It was talked about in the '60s, but it ran into a lot of obstacles," he said. "To the extent that the Russians are seriously revisiting this is pretty interesting."
The technology could change the balance of power, though Barrie questioned whether Moscow was close to deploying it.
"Does reality mean you have an item in the budget saying, 'Develop nuclear propulsion for a missile?'" he posed to the Times. "Or does it mean, 'We're going to have one ready to use soon?'
"I'd certainly want to see more evidence to believe that."