KYIV, Ukraine — The top U.S. and British diplomats traveled together to the Ukrainian capital Wednesday to underscore their commitment to the country in its war with Russia, and Ukrainian officials pressured the visitors to let them use Western-provided long-range missiles against targets inside Russia.

The rare joint visit by U.S. Secretary of State Antony Blinken and British Foreign Secretary David Lammy unfolded as Russia’s bigger and better-equipped army bears down on Ukraine’s eastern Donetsk region and pounds the country with missiles, glide bombs and drones that claim many civilian casualties.

Lammy said the 2 1/2-year conflict is at a “critical” juncture following Ukraine’s daring incursion last month into Russia’s Kursk region, even as it tries to defend against its neighbor’s aerial attacks on cities across the country.

“We convey the deepest condolences for the shocking attacks that we have seen, over the loss of civilian life, particularly women and children — horrific, barbaric, unbelievable,” Lammy said.

He noted that Britain is setting aside 3 billion pounds ($3.9 billion) a year to help Ukraine.

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Tensions Over Long-Range Weapons

But relations between Ukraine and its Western partners have been increasingly strained by Kyiv’s repeated appeals for the West’s authorization to use long-range weapons from the United States and other allies to strike targets deeper inside Russia.

That issue has become more urgent given Russia’s latest reported acquisition of ballistic missiles from Iran, but Western leaders have balked at the request, fearing that, if granted, it could escalate the war.

U.S. President Joe Biden has allowed Ukraine to fire U.S.-provided missiles across the border into Russia in self-defense, but has largely limited the distance they can be fired.

Ukrainian President Volodymyr Zelenskyy said he hoped for changes to those limitations.

“Let’s count on some strong decisions, at least,” he said. “For us, it’s very important.”

He said he hoped to speak to Biden later this month, noting that U.S. military and financial support is crucial.

“We rely heavily on it, and frankly, we can’t prevail without it,” Zelenskyy said.

However, U.S. Defense Secretary Lloyd Austin last week pushed back on the idea that long-range strikes would be a game-changer.

“I don’t believe one capability is going to be decisive, and I stand by that comment,” Austin said at a meeting of allied military leaders in Germany. The Ukrainians have other means to strike long-range targets, he added.

Ukrainian Prime Minister Denys Shmyhal told Lammy he hoped an agreement on using long-range assets “for strikes on the territory of our enemy” could be reached. “We hope for your help and support in this issue.”

Shmyhal described the meeting with Lammy in Kyiv as “intense” but gave no other details in his post on his Telegram channel.

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Challenges Ahead for Ukraine

A hard winter likely lies ahead for Ukraine. Its power grid is under severe strain after Russian missiles and drones knocked out around 70% of the country’s generation capacity.

Kyiv officials will also have to navigate the outcome of the U.S. election in November, which could produce important policy shifts in Washington. Former President Donald Trump said in a presidential debate Tuesday that he wants the war to end but did not clearly say he wants Ukraine to win.

The top U.S. and British diplomats reached the Ukrainian capital by train from Poland.

Blinken traveled from London, where he accused Iran of providing Russia with Fath-360 short-range ballistic missiles, calling the move a “dramatic escalation” of the war.

Referring to those missiles, Shmyhal added: “Russia’s use of weapons from its terrorist allies to strike at Ukraine continues their genocidal war and terrorism on our territory. We must be able to respond to such terrorism in kind by destroying military targets on their territory to ensure greater safety for our citizens.”

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Wednesday’s visit came ahead of British Prime Minister Keir Starmer’s planned trip to Washington, where he will meet Biden at the White House on Friday. Ukraine’s request for permission to strike Russian targets is due to feature in the discussion.

The visit was, unusually, announced in advance — a public signal of American and British support for Ukraine.

As Blinken and Lammy arrived in Kyiv, the U.K. announced it would ban 10 commercial ships it accuses of illicitly transporting Russian oil in violation of international sanctions. The U.K. government said the vessels would be barred from British ports and could be detained if they enter.