NEW YORK — Russia is making plans to attack Ukraine’s nuclear power plants, Ukrainian President Volodymyr Zelensky warned fellow world leaders at the United Nations on Wednesday, issuing a stark call for global leadership to help him attain peace as his country stares down a cold, dark winter with most of its energy infrastructure destroyed.

In his highest-platform address during a week of high-stakes diplomacy, Zelensky singled out his Russian counterpart, President Vladimir Putin, and said Ukraine has a right to its territorial integrity. He decried Moscow’s veto on the U.N. Security Council, which has stymied the strongest global repercussions for Russia’s full-scale invasion of Ukraine.

Zelensky plans to meet President Joe Biden on Thursday at the White House, where he will present ideas — billed as a “victory plan” — for ending the conflict. He also is seeking permission to use long-range U.S. missiles for strikes deep inside Russian territory.

“Recently, I received yet another alarming report from our intelligence. Now, Putin does seem to be planning attacks on our nuclear power plants and infrastructure, aiming to disconnect the plants from the power grid,” Zelensky said, speaking from the high rostrum of the main United Nations hall. “Any missile or drone strike or any critical incident in the energy system could lead to a nuclear disaster. A day like that must never come.”

He said his country fears its toughest winter yet, as Ukrainian officials privately warn their international allies that many of their citizens could face most of their days during the bitter winter months without heat or power.

“Just imagine, please, your country, with 80 percent of its energy system gone. … What kind of life would that be?” Zelensky said. “If, God forbid, Russia causes a nuclear disaster at one of our nuclear power plants, radiation will not respect state borders.”

The Russian Embassy in Washington did not immediately respond to a request for comment.

Zelensky sought to drum up support from countries around the world, including less-wealthy nations where Russian propaganda and investment have been especially effective at drawing popular sympathy.

“The world has already been through colonial wars and conspiracies of great powers at the expense of those who are smaller,” he said. “Every country, including China, Brazil, European nations, African nations, Middle East, all understand why these must remain in the past. And Ukrainians will never accept, will never accept why anyone in the world believes that such a brutal colonial past, which suits no one today, can be imposed on Ukraine now.”

Ukrainian leaders have begun to circulate ideas and elements of their plan to bring the two-plus years of fighting to an end, though they have not yet made public their full strategy, and it remains unclear whether it will be enough to form the basis of negotiations with Russia. Diplomats who have spoken with Ukrainian officials say that one key aspiration is NATO membership, something that Kyiv has been seeking for years.

U.S. officials, though broadly supportive of Ukraine, have been cautious about making major policy shifts as Biden hears from Ukraine and other allies about the desire to hit deeper inside Russia.

“Look, every step along the way since before the Russian invasion, we’ve tried to make sure that Ukraine had what it needed when it needed it to defend against Russian aggression,” Secretary of State Antony Blinken told ABC News earlier Wednesday when asked whether the White House would green-light Kyiv’s request to use longer-range missiles against Russian territory. “We’ve been working to adapt and adjust depending on the battlefield needs. … We’ll continue to do that.”