WASHINGTON — A senior American general told Congress on Wednesday that Russia has deployed a prohibited cruise missile, the first public confirmation by the United States that the Kremlin had fielded the weapon in violation of a landmark arms control agreement.
The missile is believed to have been moved in December from a test site in southern Russia to an undisclosed operational base.
“We believe that the Russians have deployed a land-based cruise missile that violates the spirit and intent of the Intermediate Nuclear Forces Treaty,” Gen. Paul Selva, the vice chairman of the Joint Chiefs of Staff, told the House Armed Services Committee. “The system itself presents a risk to most of our facilities in Europe,” he added. “And we believe that the Russians have deliberately deployed it in order to pose a threat to NATO and to facilities within the NATO area of responsibility.”
The New York Times reported last month that Russia had deployed a battalion of the prohibited missiles. A typical battalion has four launchers, each of which is equipped with six missiles.
While senior Trump administration officials have not said where the new unit is based, there has been speculation in media reports that a missile system with similar characteristics is deployed in central Russia. The Times also noted that a second battalion was staged at a missile test range at Kapustin Yar, in southern Russia near Volgograd.
Russia’s foreign ministry criticized the article as an example of “fake news.”
The treaty Russia is accused of violating bans the testing, production and possession of American and Russian intermediate-range missiles based on land. Commonly called the I.N.F. treaty, it was signed in 1987 by President Ronald Reagan and Mikhail S. Gorbachev, the Soviet leader, and is regarded as one of the cornerstones of arms control.
General Selva appeared skeptical during his congressional testimony about the prospects of persuading the Russians to remedy the violation.
“I don’t have enough information on their intent to conclude, other than that they do not intend to return to compliance,” he told the lawmakers.
General Selva added that the Pentagon was considering steps the United States and its allies could take to pressure the Russians to comply, but had not yet determined what “leverage points” might be effective.
“I don’t know what those points are at this point in time,” he said.
The Obama administration, starting in 2013, sought to persuade the Russians to correct the violation while the missile was still in the test phase. But the Russians have denied they have violated the treaty and responded with their own allegations, which the Americans have dismissed as specious.
American lawmakers say it is very unlikely that the Senate would ratify a new agreement requiring deeper cuts in long-range nuclear arms unless the dispute over Russian compliance with the I.N.F. treaty is resolved.
In a February interview with Reuters, President Trump said he was concerned about the alleged violation and planned to take it up with President Vladimir V. Putin of Russia.
“To me it’s a big deal,” said Mr. Trump, who added that he would raise the matter with Mr. Putin “if and when we meet.”
If the Russians agreed to eliminate the new cruise missile, verifying that the missile was no longer deployed could require intrusive on-site inspections. The mobile launcher for the cruise missile is very similar to the mobile launcher used for the Iskander, a nuclear-tipped short-range system that is permitted under arms control treaties.
Having failed to persuade the Russians to fix the alleged violation, some military experts say the United States could increase the pressure by announcing plans to expand missile defenses in Europe or deploying sea-based or air-based nuclear missiles.
But many say that the United States should seek to avoid a heated debate within the alliance by proposing the deployment of a new generation of land-based intermediate-range missiles in Europe. The Russian cruise missile is also a concern for the United States’ Asian allies. Since the system is mobile, it could easily be moved across Russia, depending on its potential target.