KYIV, Ukaine — Washington is facing mounting pressure from NATO and several key European allies to lift restrictions and allow Ukraine to use the full force of U.S.-provided weapons to strike military targets inside Russia.

The demands reflect new alarm in the West over Russian battlefield advances in recent days, including the seizure of several villages in the Kharkiv and Donetsk regions and brutal bombings that have killed dozens of civilians.

“If you cannot attack the Russian forces on the other side of the front line because they are on the other side of the border, then of course you really reduce the ability of the Ukrainian forces to defend themselves,” NATO Secretary General Jens Stoltenberg, the alliance’s top political official, said during a visit to Bulgaria on Monday.

NATO’s parliamentary assembly, meanwhile, issued a declaration urging that the restrictions be lifted.

The United States and other NATO allies, including Germany and Italy, have long refused to let Ukraine use their weapons to strike inside Russia’s borders, fearing that such attacks could escalate the conflict. Senior Russian officials repeatedly have brandished Moscow’s nuclear arsenal in response to suggestions of greater Western involvement in the war.

Kyiv for months has argued that the limitations have blocked its military from destroying key Russian hardware to prevent deadly attacks — a view now being voiced by several major European leaders.

Ukraine instead has relied on homemade drones to strike inside Russia — a tactic that has yielded some results, including apparent damage to a Russian radar battery near the city of Orsk this weekend, some 1,100 miles from Ukraine.

“We need to work together and put pressure not only on Russia but also on our partners to give us the opportunity to defend ourselves against Russia,” Ukrainian President Volodymyr Zelenskyy said Monday in Spain, where he signed a 10-year bilateral security deal that will provide Ukraine with more than $1 billion in Spanish aid.

Dutch Defense Minister Kajsa Ollongren said Tuesday that restrictions on Ukraine’s ability to strike inside Russia have left Kyiv fighting “with one hand tied behind its back.” Lifting these limits “should not be a subject of debate,” Ollongren said. “I hope that other countries with a different position will change it.”

Latvian President Edgars Rinkevics told CNN on Monday that partners who oppose Ukraine using their weapons to strike targets on Russian soil should “reconsider that decision as soon as possible.”

The recent attacks on Kharkiv are “the consequence of our inability to provide Ukraine with weapons and also putting restrictions [on using] those weapons to strike military targets in Russia,” Rinkevics said.

“There is not any rational, pragmatic reason not to allow Ukraine to use those weapons against Russia in a way that is most efficient,” he said. Claims that such strikes could cause Russia to further escalate the war, he added, are “not grounded in [a] really sound assessment of the reality.”

British Foreign Secretary David Cameron, during a visit to Kyiv this month, appeared to give the green light for Ukraine to use British weapons on Russian territory, saying Ukraine should decide how best to use the weapons. “Just as Russia is striking inside Ukraine, you can quite understand why Ukraine feels the need to make sure it’s defending itself,” he said.

A Ukrainian military official, however, said the British government had never formally communicated the lifting of restrictions.

“There is no official permission,” the official said, speaking on the condition of anonymity to discuss a sensitive security matter. The official added that British Storm Shadow air-launched cruise missiles, which have a range of more than 150 miles, have never been used to strike a target outside sovereign Ukrainian territory. (They have been used to hit Crimea, which Russia illegally annexed in 2014.)

“First, [politicians] throw this idea into the information space to see the reaction of their people,” the official said. “After that, they decide: ‘Yes, we allow,’ or ‘No, we do not allow.’”

European Union defense ministers at a meeting Tuesday were also set to discuss the issue of allowing strikes inside Russia, said the bloc’s foreign policy chief, Josep Borrell. “Do we allow our arms to be used, further, in Russian territory? Well, some member states have started deciding that — taking this constraint out,” Borrell said. “Another important thing to discuss today.”

The issue remains contentious in Europe, where some nations fear that Russia will retaliate and spread the conflict beyond Ukraine if Western equipment is used to strike Russia’s sovereign territory.

“I don’t know why Stoltenberg said such a thing — I think we have to be very careful,” Italian Prime Minister Giorgia Meloni said in an interview with Italian television Sunday, replying to comments by Stoltenberg pushing for a policy shift that were published Friday by the Economist.

German Chancellor Olaf Scholz said Sunday that he did not support any change to Germany’s policy on strikes inside Russia. “We have clear rules agreed with Ukraine for the arms deliveries we have made so far,” Scholz said. “And they work. At least that’s my theory.”

Stoltenberg has insisted that any decision to expand Ukraine’s ability to strike Russian targets should be made by individual nations, not NATO, allowing the alliance to keep some distance from the war.

Kremlin spokesman Dmitry Peskov has already accused NATO of direct involvement in the war and described Stoltenberg’s remarks as “an absolutely irresponsible position.”

Even as the debate plays out in Europe, various countries are pledging new support to Ukraine. After his trip to Spain, Zelenskyy made an appearance Tuesday in Belgium, where he was promised $1 billion in assistance and 30 F-16 fighter jets by 2028.

Meanwhile, Ukraine’s military announced this week that France planned to send military trainers to Ukraine, but later walked back the statement, saying Ukraine is “still in discussions with France and other countries on this issue.”

When asked about the remark, the French Defense Ministry pointed to the Ukrainian clarification and said only that it continued to work with Kyiv on the issue. French President Emmanuel Macron has said previously that Western countries should not rule out sending troops to Ukraine.

Polish Foreign Minister Radoslaw Sikorski echoed Macron’s comments this week, saying in an interview published Tuesday that Poland should not rule out such a move.

“We need to keep Putin guessing about our intentions,” Sikorski said.

Speaking from Spain on Monday, Zelenskyy said Russia has dropped some 3,200 guided aerial bombs on Ukraine this month alone.

“How do you fight that? There aren’t enough air defense missiles to stop thousands of bombs a month,” Zelenskyy said. “Those partners who are afraid to give us this or that weapon should understand that air defense is defense, not offense.”

Isabelle Khurshudyan in Kyiv and Emily Rauhala in Brussels contributed to this report.

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