‘Dictators Do Not Go on Vacation,’ Zelensky Warns Washington and Europe

President Volodymyr Zelensky of Ukraine called on world leaders not to abandon his country, citing the recent death of a Russian dissident as a reminder that President Vladimir V. Putin of Russiawould continue to test the international order, and pushing back against the idea of a negotiated resolution to the war.

Mr. Zelensky, speaking on Saturday at the Munich Security Conference, said that if Ukraine lost the war to Russia, it would be “catastrophic” not only for Kyiv, but for other nations as well.

“Please do not ask Ukraine when the war will end,” he said. “Ask yourself why is Putin still able to continue it.”

The two topics that have loomed over nearly every discussion at the yearly meeting of world leaders have been Russia and the potential weakening of trans-Atlantic relations, amid an increasingly pessimistic assessment of Kyiv’s ability to beat Moscow.

Mr. Zelensky’s speech on Saturday came as Ukrainian forces retreated from a longtime stronghold, Avdiivka, giving Russian troops their first significant victory in almost a year.

And it came a day after attendees of the conference were shaken by the news that the prominent dissident Aleksei A. Navalny had died in a Russian Arctic penal colony. It was a stark reminder, Mr. Zelensky warned, of how Moscow would continue to test the Western-backed international rules-based order.