President Vladimir V. Putin of Russia said he would be able to position tactical nuclear weapons in Belarus by the summer, a move that threatened to increase tensions with the United States and Europe while his forces wage war in Ukraine.
The Russian leader has repeatedly raised the specter of using nuclear weapons since ordering the full-scale invasion of Ukraine last year. While U.S. officials have said they have seen no effort by Russia to move or employ its nuclear weapons and believe the risk of their use is low, worries have lingered.
Mr. Putin’s remarks about stationing weapons in Belarus — a prospect he first floated last year — could again be saber rattling. It would not necessarily change the battlefield calculus: Any targets that Moscow can strike from Belarus, which borders three NATO members, it can already strike from Russian territory.
American officials indicated that they did not immediately sense an escalation.
In an interview with state media released online on Saturday, Mr. Putin said that construction on a storage facility for tactical nuclear weapons in Belarus would be completed by July 1, according to the Tass news agency, though it was not immediately clear if or when nuclear weapons would be moved there.
Increasingly isolated from the West, Mr. Putin has been relying on allies like Belarus — a country bordering Ukraine that was used as a staging ground for the full-scale invasion. Mr. Putin said that President Aleksandr G. Lukashenko of Belarus had requested that Moscow station the weapons on his soil.
Mr. Putin’s statements came after Russia criticized Britain for giving Ukraine weapons with depleted uranium, falsely claiming that the material had a “nuclear component.” But Mr. Putin cast his announcement as “nothing unusual,” saying the United States has long deployed its own nuclear weapons within the borders of its European allies.
“We will do the same,” Mr. Putin said on Saturday, according to the state-run Tass agency. “Without violating, I want to emphasize this, our international obligations on the nonproliferation of nuclear weapons,” he added.
There was no immediate comment from Mr. Lukashenko of Belarus.
Oleksiy Danilov, the head of the Ukrainian National Security and Defense Council, accused the Kremlin of taking Belarus “as a nuclear hostage.” Germany’s foreign ministry called Mr. Putin’s announcement “another attempt at nuclear intimidation,” according to the German news agency D.P.A.
Late on Saturday, the Pentagon released an email statement saying: “We have seen reports of Russia’s announcement and will continue to monitor this situation.” It added: “We have not seen any reason to adjust our own strategic nuclear posture nor any indications Russia is preparing to use a nuclear weapon. We remain committed to the collective defense of the NATO alliance.”
The Institute for the Study of War, a Washington-based research group, dismissed Mr. Putin’s announcement as an “information operation” with little risk of escalation.
“Putin is attempting to exploit Western fears of nuclear escalation,” it said, adding that the group “continues to assess that Putin is a risk-averse actor who repeatedly threatens to use nuclear weapons without any intention of following through in order to break Western resolve.”
Russia has as many as 2,000 tactical nuclear weapons, which have a lower yield than the strategic kind that can traverse entire continents. A tactical nuclear weapon has never been used in combat, but one could be deployed in a number of ways, including by missile or artillery shell.
Christopher F. Schuetze contributed reporting.