Putin Claims Russia Successfully Tested a Nuclear-Powered Missile.

President Vladimir V. Putin claimed on Thursday that Russia had successfully tested the Burevestnik, an experimental nuclear-powered cruise missile, and had almost completed work on a new type of nuclear-capable ballistic missile.

“No one in their sound mind will use a nuclear weapon against Russia,” Mr. Putin said.

Mr. Putin, speaking in the Black Sea city of Sochi at an event of the Valdai Discussion Club, a Kremlin-affiliated research institute, did not say when the test had occurred or offer any details, including how far the missile flew. His claim of a successful launch could not be independently confirmed.

The New York Times reported on Monday that Russia was either preparing to test or had already tested the Burevestnik, also called the SSC-X-9 Skyfall, which has a designed range of more than 10,000 miles. Satellite imagery taken in late September showed several vehicles at the launchpad of a remote Arctic base — including one with a trailer that corresponded to the dimensions of the Burevestnik — and a mobile weather cover for the missile or launchpad that was retracted from its typical position at least twice between Sept. 20 and Sept. 28.

There were at least 13 trials of the missile between 2017 and 2019 and all failed, according to a report by the Nuclear Threat Initiative, an arms-control organization. A 2019 operation to recover a Burevestnik missile that crashed during a test caused an explosion that killed seven people, according to U.S. officials.

Daryl G. Kimball, executive director of the Arms Control Association, a nonpartisan group based in Washington that advocates nuclear nonproliferation, described the missile as “exotic” and said, “It is dangerous in its testing and development phase.”

Speaking to The Times before Mr. Putin’s Valdai appearance, Mr. Kimball added that even with a successful launch — meaning the activation of the missile’s nuclear reactor in flight as well as a significant fight distance — the Burevestnik would still be years away from “operational deployment.”

The Valdai event is usually seen as one of Mr. Putin’s annual opportunities to articulate his worldview and his international and domestic political agendas. This year, Mr. Putin spoke as rescue workers were trying to pull dead and wounded people from the site of a Russian missile strike in the town of Groza in northeastern Ukraine that killed more than 50, according to Ukrainian officials.

In his remarks, Mr. Putin added that he saw “no need” to change the country’s nuclear doctrine but that it was possible Moscow could revoke its ratification of the Comprehensive Nuclear Test Ban Treaty. The treaty, an international agreement that bans all nuclear explosions, was established more than 20 years ago but has not yet ratified by some of its signers, including the United States.

As in years past, Mr. Putin used the address to accuse the West of being a hypocritical “hegemon” that sought to punish any countries that did not “blindly follow” its agenda.

“Attempts to establish a monopoly in world affairs are doomed to fail,” said Mr. Putin, who appeared relaxed throughout his hourslong appearance, making jokes and interacting with the members of the audience who questioned him. Lasting peace, he said, “will only be established when everyone begins to feel safe, understand that their opinions are respected and that there is a balance in the world.”

Repeating a frequent justification for the invasion of Ukraine, Mr. Putin blamed Western meddling in Ukraine over the past decade. “We try to stop it,” he said of the war.