Russia on Monday threatened to strike British military facilities and said it would hold drills simulating the use of battlefield nuclear weapons amid sharply rising tensions over comments by senior Western officials about possibly deeper involvement in the war in Ukraine.

After summoning the British ambassador to the Foreign Ministry, Moscow warned that Ukrainian strikes on Russian territory with U.K.-supplied weapons could bring retaliatory strikes against British military facilities and equipment on Ukrainian soil or elsewhere.

Putin’s Inauguration and Victory Day

The remarks came on the eve of Russian President Vladimir Putin’s inauguration to a fifth term in office and in a week when Moscow on Thursday will celebrate Victory Day, its most important secular holiday, marking its defeat of Nazi Germany in World War II.

The drills are a response to “provocative statements and threats of certain Western officials regarding the Russian Federation,” the Defense Ministry said in a statement.

It was the first time Russia has publicly announced drills involving tactical nuclear weapons, although its strategic nuclear forces regularly hold exercises. Tactical nuclear weapons include air bombs, warheads for short-range missiles and artillery munitions and are meant for use on a battlefield. They are less powerful than the strategic weapons — massive warheads that arm intercontinental ballistic missiles and are intended to obliterate entire cities.

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Warning to Ukraine’s Western Allies

The Russian announcement was a warning to Ukraine’s Western allies about becoming more deeply engaged in the 2-year-old war, where the Kremlin’s forces have gained an upper hand amid Ukraine’s shortage of manpower and weapons. Some of Ukraine’s Western partners have previously expressed concern that the conflict could spill beyond Ukraine into a war between NATO and Russia.

French President Emmanuel Macron repeated last week that he doesn’t exclude sending troops to Ukraine, and U.K. Foreign Secretary David Cameron said Kyiv’s forces will be able to use British long-range weapons to strike targets inside Russia. Some other NATO countries providing weapons to Kyiv have balked at that possibility.

The Kremlin branded those comments as dangerous, heightening tension between Russia and NATO. The war already has placed significant strain on relations between Moscow and the West.

Kremlin spokesman Dmitry Peskov said Monday that Macron’s recent statement and other remarks by British and U.S. officials had prompted the nuclear drills.

“It’s a new round of escalation,” Peskov said, referring to what the Kremlin regarded as provocative statements. “It’s unprecedented and requires special attention and special measures.”

Russia’s Foreign Ministry summoned both the French and British ambassadors. It urged the British ambassador “to think about the inevitable catastrophic consequences of such hostile steps from London.”

Sweden’s Foreign Minister Tobias Billström said the nuclear exercises “contribute to increasing instability.”

“In the current security situation, Russia’s actions may be considered particularly irresponsible and reckless,” Billström told Swedish news agency TT.

Dmitry Medvedev, the deputy head of Russia’s Security Council that’s chaired by Putin, said in his typically hawkish fashion that the comments by Macron and Cameron risked pushing the nuclear-armed world toward a “global catastrophe.”

It wasn’t the first time Europe’s military support for Ukraine has prompted nuclear saber-rattling. In March 2023, after the U.K.’s decision to provide Ukraine with armor-piercing shells containing depleted uranium, Putin said he intends to deploy tactical nuclear weapons on the territory of Ukraine neighbor Belarus.

The ministry said the exercise is intended to “increase the readiness of non-strategic nuclear forces to fulfill combat tasks” and will be held on Putin’s orders. The maneuvers will involve missile units of the Southern Military District along with the air force and the navy, it said.

The Russian announcement stirred little reaction in Ukraine, where the spokesman for the Military Intelligence agency, Andrii Yusov, said on national television: “Nuclear blackmail is a usual practice of Putin’s regime; it does not constitute major news.”

Western officials have blamed Russia for threatening a wider war through provocative acts. NATO countries said last week they are deeply concerned by a campaign of hybrid activities on the military alliance’s soil, accusing Moscow of being behind them and saying they represent a security threat.

Peskov dismissed those claims as “new, unfounded accusations leveled at our country.”

Germany said Monday it recalled its ambassador to Russia for a week of consultations in Berlin following an alleged computer hack of Chancellor Olaf Scholz’s party.

Meanwhile, Ukrainian drones hit two vehicles Monday in Russia’s Belgorod region, killing six people and injuring 35 others, including two children, local authorities said. The area has been hit by Kyiv’s forces in recent months.

One of the vehicles was a minibus carrying farm workers, Belgorod Gov. Vyacheslav Gladkov said.

It was not possible to independently confirm the report.

While Ukraine’s army is largely pinned down on the 1,000-kilometer (600-mile) front line due to a shortage of troops and ammunition after more than two years of fighting, it has used its long-range firepower to hit targets deep inside Russia.

In what has largely been a war of attrition, Russia also has relied heavily on long-range missile, artillery and drones to wreak damage on Ukraine.

The Kremlin’s forces kept up their bombardment of Ukraine’s power grid, with a nighttime Russian drone attack targeting energy infrastructure in Ukraine’s northern region of Sumy. Multiple towns and villages in the region, including Sumy, lost power, regional authorities said.

Russia attacked Ukrainian targets with 13 Shahed drones overnight, 12 of which were intercepted in the Sumy region, Ukraine’s air force said.