New York ― Ukrainian President Volodymyr Zelenskyy on Tuesday delivered an impassioned speech to world leaders at the United Nations General Assembly, pushing for sustained support for his embattled nation's fight against Russia as he embarked on a delicate mission to bolster his cause globally and in Washington, Ukraine's most important partner.

Zelenskyy's rare visit across the Atlantic came at an urgent moment in his efforts to maintain robust aid for Ukraine's fight, amid increasing concern among leaders of the Global South and Republicans in Congress who say the war is consuming too many resources and drawing away from other priorities. Over three-and-a-half days of meetings and speeches, the Ukrainian leader is charged with finding ways to solidify support as portions of the world seek to move on.

Even as he embarked on his mission to confront skeptical voices, Zelenskyy received a warm welcome inside the grand U.N. chamber. But in a possible sign of the challenges he faces, he delivered his address to a half-full house, with many delegations declining to appear and listen to what he had to say.

"Mass destruction is gaining momentum," Zelenskyy said. "The aggressor is weaponizing many other things and those things are used not only against our country, but against all of yours as well, fellow leaders."

And after a more than a year and a half of war, leaders from some developing nations are increasingly frustrated that the effort to support Ukraine is taking away, they say, from their own struggles to drum up enough money to adapt to a warming world, confront poverty and ensure a more secure life for their citizens.

In Washington, meanwhile, a growing faction of the Republican Party is rebelling against further spending on military aid for Ukraine, following former president Donald Trump's lead in questioning whether it should be an American priority. Although most Democrats and a significant portion of Republicans remain staunchly behind Kyiv, the blowback among House Republicans may be enough to derail an effort to approve a supplemental package of aid for Kyiv. House Speaker Kevin McCarthy, R-Calif., has been vague about his plans for such a meeting, but implied Tuesday that one would take place during Zelenskyy's Thursday visit.

The continuing economic and military support to Ukraine is estimated to be about $73 billion globally.

Over the course of his 15-minute speech, Zelenskyy warned wavering leaders not to trust Russia, which he said has sought to exploit divisions with propaganda campaigns across Africa, Latin America and parts of Asia.

"Evil cannot be trusted. Ask Prigozhin if one bets on Putin's promises," Zelenskyy said, referencing to the former leader of the Wagner mercenary group, who died last month when his plane exploded after it departed a Moscow airport in an incident that Western nations have blamed on the Kremlin.

He sought to connect global food shortages and rising energy prices to Russia's aggression against his country, drawing a link between the conflict and some of the problems that leaders of less wealthy nations say are being ignored as the United States and Europe focus on dealing with the conflict.

And he said that at a moment when global warming is causing drought, extreme weather and human destruction, humanity could scarcely deal with a bloody war of choice on top of it all.

"When all of this is happening, a natural disaster in Moscow decided to launch a big war and kill tens of thousands of people. We have to stop it," Zelenskyy said, declaring that respect for the rule of law and the U.N. Charter was important to all nations, not just his own.

Zelenskyy's visit to the United States was intended to take advantage of his powerful oratory to sway wavering voices. A comedian and actor by profession, the Ukrainian president has proved to have formidable powers of persuasion on the world stage. The trip started with a visit Monday to a New York hospital where wounded Ukrainian soldiers are being treated and will conclude Thursday with a visit to the White House ― his second since the war began ― and meetings with congressional leaders.

It was the Ukrainian leader's first in-person trip to the United Nations since the war started in February 2022. At last year's General Assembly, he delivered remarks from Ukraine by video link. At the time, Ukrainian troops were engaged in a lightning-quick operation that ousted Russian troops from the northeast Kharkiv region. He visited Washington in December, riding off that success after recapturing significant portions of the territory that Russia had taken early in its invasion.

This moment is trickier, after Ukrainian troops pressing a counteroffensive for months have not made the major advances Kyiv and its backers had hoped for. Still, Ukraine has shown its clear ability to hold back Russia and prevent major advances along the front lines. Instead, the war has evolved into a grinding battle of trenches, minefields, and artillery and rocket volleys. To wit, Russian forces launched an overnight missile and drone attack Tuesday that pummeled cities as far west as Lviv, where officials said a humanitarian aid warehouse was destroyed.

The U.N. General Assembly has voted overwhelmingly to condemn the invasion and demand respect for Ukraine's borders but the Kremlin has ignored the calls for withdrawal of its troops.

Despite Russia's flagrant invasion of its neighbor, the deaths of thousands of soldiers and civilians, and allegations of war crimes by Russian troops, some countries in Asia, Africa and South America have been reluctant to enforce Western sanctions against Russia, for fear of disrupting their economic and diplomatic links with Moscow.

Zelenskyy's Ukrainian allies said they were depending on his oratory to change minds during his U.S. visit.

"I've seen him at numerous international events and meetings, and I know he has a type of superpower, the capacity to really persuade people in person," Ukrainian Foreign Minister Dmytro Kuleba said in a statement to The Washington Post. Kuleba accompanied Zelenskyy to New York.

"We are now at a critical juncture in time, as Ukraine continues to advance on the battlefield," Kuleba said, "and it is critical to sustain and strengthen worldwide support for Ukraine."

Ukrainian forces are making slow headway and suffering heavy losses in their counteroffensive, launched at the start of the summer, as they advance on entrenched Russian positions through heavily mined fields.

"There's no intention whatsoever by the Ukrainians to stop fighting during the winter," Gen. Mark A. Milley, chairman of the Joint Chiefs of Staff, said Tuesday in remarks in Germany, where he and Defense Secretary Lloyd Austin were meeting Ukrainian military leaders alongside other backers to plan further support. "They have a strategic initiative right now."

In an interview earlier this month, Milley said Ukraine had about 30 to 45 days of fighting weather left before inclement weather set in.

U.S. intelligence officials also have predicted that Ukraine will not reach the city of Melitopol during the current push, one of the key objectives of the counteroffensive this year.

On Monday, officials said Ukrainian troops had liberated the village of Klishchiivka in eastern Ukraine, near the city of Bakhmut, which could provide a foothold for further advances. The news, while positive, also underlined the slow pace of Ukrainian troops' progress.

Russia, meanwhile, sent 30 self-destructing drones and a ballistic missile raining down across Ukraine overnight, Ukraine's air force said Tuesday. More than half of the drones were directed at the western Lviv region, far from the front lines, the head of the local regional administration, Maksym Kozytskyy, said on social media.

Lviv Mayor Andriy Sadovyi said the Lviv region had "practically no military facilities" and was used primarily as a production center and hub for humanitarian operations.

"Most likely, [the Russians] get satisfaction when they cause pain," he said.

Stern reported from Kyiv and Morgunov reported from Lviv, Ukraine. Isabelle Khurshudyan in Lviv, Kostiantyn Khudov in Kyiv, Missy Ryan in Ramstein, Germany, and Abigail Hauslohner in Washington contributed to this report.

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