Western sanctions will not deter Moscow from carrying out plans of moving tactical nuclear weapons into Belarus, the Kremlin said Monday. The European Union threatened to impose sanctions on Belarus after Russia announced it would store the weapons in the Kremlin-aligned country, which shares a long border with northern Ukraine.

In Zaporizhzhia, Ukrainian President Volodymyr Zelensky met with Rafael Mariano Grossi, director general of the International Atomic Energy Agency. They discussed the Zaporizhzhia nuclear power plant and heavy fighting in its vicinity that has raised concerns about a potential radioactive disaster. They also visited a hydroelectric station on the Dnieper River that helps maintain operations at the plant.

Ukrainian President Volodymyr Zelensky meets with U.N. atomic energy chief Rafael Mariano Grossi during a visit to Zaporizhzhia, Ukraine on Monday. Efrem Lukatsky/Associated Press

In a nightly address, Zelensky said Russia has held the power plant hostage for more than a year and continues to use it for “radiation blackmail of the world.” The longer the Russian occupation of the plant continues, “the greater will be the threat to the security of Ukraine, the whole of Europe and the world,” he said.

“Russia’s plans certainly cannot be affected by such a reaction,” Kremlin spokesman Dmitry Peskov told reporters Monday when asked about the Western reaction to Russian President Vladimir Putin’s announcement over the weekend on moving nuclear weapons to Belarus.

Nikolai Patrushev, head of the Russian Security Council, said Monday that Russia has “advanced unique weapons to eliminate any adversary,” and he accused NATO nations of providing Kyiv with weapons and intelligence. Patrushev said in an interview with state-run Rossiyskaya Gazeta that it was “dangerous” and “shortsighted foolishness” for American officials to believe that, in case of direct conflict with Russia, the United States “can deliver a preemptive missile strike” and that “Russia won’t be able to retaliate.”

The European Union’s foreign policy chief said the bloc “stands ready to respond with further sanctions” if Belarus hosts Russian tactical nuclear arms. Josep Borrell called the plan a “threat to European security,” though European and U.S. officials played down any immediate risk. “Belarus can still stop it; it is their choice,” Borrell said.

Ukraine’s Foreign Ministry called for an urgent meeting of the U.N. Security Council to counter what it described as “the Kremlin’s nuclear blackmail.”

NATO called Russia’s nuclear rhetoric “dangerous and irresponsible” and said it was “closely monitoring the situation.”

Grossi plans to visit the Zaporizhzhia nuclear plant this week for the second time since the IAEA installed a permanent crew there in September, according to a statement issued Saturday. “The situation at the Zaporizhzhia Nuclear Power Plant is still precarious,” Grossi said in the statement.

Russian President Vladimir Putin, right, and Belarusian President Alexander Lukashenko pose for a photo prior to their talks at the Novo-Ogaryovo state residence, outside Moscow, Russia on Feb. 17. Vladimir Astapkovich, Sputnik, Kremlin Pool Photo via AP, file

Mao Ning, a spokeswoman for China’s Foreign Ministry, said Monday that all sides of the “Ukraine crisis” should focus on “diplomatic” efforts to reach a peaceful settlement.” During a news conference, Mao also noted that the leaders of five nuclear-armed states – China, France, Russia, Britain and the United States – stressed in a joint statement last year the importance of avoiding a war between nuclear-weapon states and reducing “strategic risks.”

The actions of the “two unpredictable dictatorial regimes” led by Putin and Belarusian President Alexander Lukashenko are “dragging Belarus further into the war,” Lithuania’s Foreign Ministry said. The country, an E.U. member, will call for new sanctions, it said in a statement.

Polish Prime Minister Mateusz Morawiecki said he is “cautiously optimistic” about support from U.S. Republicans for Ukraine and minimized concerns that GOP support could falter. Morawiecki told the Financial Times that his meetings last month with Republican and Democratic lawmakers convinced him that the two parties were aligned on Ukraine.

About 71 percent of Japanese residents approve of Prime Minister Fumio Kishida’s recent visit to Kyiv, according to a poll by Nikkei and TV Tokyo. Kishida visited Ukraine earlier this month, becoming the last Group of Seven leader to do so.

Dmitry Medvedev, deputy chair of the Russian Security Council of Russia, warned against NATO weapon deliveries to Ukraine. He said Friday in an interview with Russian media that it was bringing “a nuclear apocalypse closer.” Medvedev, who previously served as president of Russia, also called for the free distribution of pirated copies of Western intellectual property on the internet, like content on Netflix, to cause “maximum damage” and as retaliation for Western-imposed sanctions on Russia.

Germany delivered 18 Leopard tanks to Ukraine on Monday, German Chancellor Olaf Scholz confirmed during a news conference with Dutch Prime Minister Mark Rutte in Rotterdam. Der Spiegel reported earlier that the Leopard tanks and “around 40 Marder infantry fighting vehicles, with which Germany is supporting Ukraine’s fight against the Russian invaders, have also arrived in the war zone.” The German Defense Ministry declined The Washington Post’s request for comment Monday.

Ukraine received its first British main battle tanks, along with other Western-made armored vehicles. Ukrainian Defense Minister Oleksii Reznikov said Monday the country had received Strykers (armored vehicles) and Cougars (mine-resistant ambush-protected and infantry mobility vehicle) from the United States and Challengers (main battle tanks) from Britain -as well as Marders (infantry fighting vehicle) from Germany. “Even a year ago, no one could have thought that the support of partners would be so powerful,” he said in a Facebook post.

Zelensky visited troops in the contested Zaporizhzhia region, according to his Telegram page. “I am honored to be here today, next to our military,” the Ukrainian leader wrote under a video that showed him awarding medals to soldiers in the southern region. Zelensky has visited several spots on the front lines recently, including some areas of fierce fighting such as Bakhmut. He also on Monday visited the southern city of Nikopol, in the Dnipropetrovsk region, which is constantly being shelled by Russian forces, according to his office.

Defending Bakhmut is a “military necessity,” Ukraine’s ground forces commander, Col. Gen. Oleksandr Syrsky, said in a Telegram post Monday after visiting the embattled city. While it is unclear when Syrsky’s visit took place, the commander said troops were facing “the most intense phase” of the lengthy fight for the eastern city. Russia continued to attack the embattled city as a Ukrainian counteroffensive loomed. Ukraine’s military said Monday that its forces still hold the eastern city.

Russia’s continued attacks on Bakhmut are not only “pointless, but actually harmful” to Moscow as it prepares for an expected Ukrainian counteroffensive in the coming weeks, according to analysts from the Institute for the Study of War think tank. Ukraine’s military said in an operational update Monday that Russia “continues to storm” the city but that Ukrainian troops were holding it.

The Washington Post’s Natalia Abbakumova contributed to this report.