Russia sent a pointed reminder on Tuesday that it could use battlefield nuclear weapons in Ukraine, releasing video of its forces beginning exercises to practice their use, two weeks after President Vladimir V. Putin ordered the provocative drills.
Video released by the Russian Defense Ministry showed a caravan of military vehicles moving down a wooded road, as well as mobile Iskander missile systems — which can deliver conventional or nuclear explosives — getting into position to launch, with their warheads blurred out. The footage also showed a supersonic strategic bomber armed with missiles and an attack aircraft being prepared for takeoff.
In a statement, the Russian Defense Ministry said the exercise, carried out near Ukraine, was aimed at preparing the force to use tactical nuclear weapons. The goal is to “unconditionally ensure the territorial integrity and sovereignty of the Russian state in response to provocative statements and threats of individual Western officials,” the ministry said.
Upon announcing the drills earlier this month, the Kremlin suggested the move was a response to comments by President Emmanuel Macron of France, who refused to rule out sending French troops to Ukraine, and David Cameron, Britain’s top diplomat, who said Ukraine could use British weapons to strike inside Russia.
Dmitri S. Peskov, the Kremlin’s spokesman, at the time called their comments “unprecedented” and described them as a “completely new round of escalation” that merited a response by Moscow.
The exercises were the clearest warning yet from Russia that it might use nuclear weapons in the course of its war against Ukraine.
“It’s transparently an effort at nuclear coercion,” said Jeffrey Lewis, a nuclear nonproliferation expert at the Middlebury Institute for International Studies. “They’ve even blurred the warhead on the Iskander ballistic missiles, which seems unnecessary but theatrical.”
The possibility of the conflict going nuclear has been there from the start, with Moscow trying to use its nuclear arsenal to deter Western nations from aiding Kyiv. The day he launched his invasion more than two years ago, Mr. Putin warned nations considering intervening to help Ukraine that they would face “consequences such as you have never seen in your entire history.”
Unlike strategic nuclear weapons, launched from great distances and with the power to obliterate whole cities, tactical nuclear warheads are designed for battlefield use. They are made to be used against limited targets, often from relatively short distances, with yields low enough to limit the destruction to a certain area.
The Russian Defense Ministry said on Tuesday the first stage of the exercise had begun in the Southern Military District, which includes much of southern Russia, in addition to areas of Ukraine that Moscow now occupies.
The drills come amid broader questions about whether Western nations should intervene more forcefully in the conflict to help the beleaguered Ukrainian military, which has struggled with shortages of ammunition and personnel, as well as delayed aid from its biggest backer, the United States.
In an interview with The New York Times published on Tuesday, President Volodymyr Zelensky of Ukraine called for NATO countries to become more directly involved in the war, particularly in helping shoot down Russian missiles. He also said he wanted to be able to use American weapons against Russian forces on Russian territory, which Washington has not allowed.
Mr. Zelensky added that fears of nuclear escalation were overblown, saying that Mr. Putin “may be irrational, but he loves his own life.”
During the drills, Russian forces practiced loading “special” warheads on the Iskander systems, which have a range of a few hundred miles, and moving them covertly into position for launch, the ministry said. The exercise also saw forces practice loading warheads onto aircraft.
U.S. officials for years have been concerned about Russia’s vast arsenal of tactical nuclear weapons, but efforts to bring them under control through diplomacy have failed amid a broader fraying of Cold War-era arms-control pacts.
Russian state news also reported on Tuesday that a former general, Ivan Popov, who spoke out against Moscow’s military leadership in a viral recording released by a Russian lawmaker last year, had been arrested on suspicion of fraud.
General Popov, the former commander of Russia’s 58th Combined Arms Army, was taken into custody as part of a criminal case involving “fraud on a particularly large scale,” the Russian state news agency Tass reported.
He lashed out at the Russian military leadership last year after being removed from his command, saying that the country’s top officer, Gen. Valery V. Gerasimov, had “treacherously and vilely decapitated our army” at a particularly sensitive moment for Russian forces. At the time, his unit had been holding off a Ukrainian counteroffensive in the Zaporizhzhia region.
The recording emerged amid the upheaval caused by a failed uprising by the mercenary chief Yevegeny V. Prigozhin.
Sergei Buinovsky, a lawyer for General Popov, told Russian news outlets that his client denied wrongdoing.
The Russian authorities have also arrested top underlings of former Defense Minister Sergei K. Shoigu in recent weeks in an anticorruption drive. The Kremlin brought in a new defense minister, the economist Andrei R. Belousov, and moved Mr. Shoigu to run the Russian security council.
Those arrests were seen as a method to deter top Russian officials from pilfering the deluge of state funds flowing into the defense sector, and as a way to boost morale for the troops, who bristle at the idea of top officials getting rich as they fight in the trenches.
But the arrest of General Popov may have the opposite effect for the Russian troops. He was generally seen as popular among the rank and file, and a number of pro-war military bloggers came to his defense on Tuesday.
“General Ivan Popov is not a thief,” Alexander Sladkov, a war correspondent for Russian state media, wrote on Telegram. “He is a soldier.”
