And he sought to tap into public rage in two videotaped speeches released on Saturday.
“The whole country saw that Melitopol did not surrender to the invaders,” he said. “Just as Kherson, Berdyansk and other cities where Russian troops managed to enter didn’t — temporarily managed to enter. And this will not be changed by putting pressure on mayors or kidnapping mayors.”
After people took to the streets, he praised their courage and suggested the war lacked popular support among Russians.
“Do you hear it, Moscow?” he asked. “If 2,000 people are protesting against the occupation in Melitopol, how many people should be in Moscow against the war?”
Mr. Zelelnsky said he had raised the fate of the mayor in calls with the leaders of Germany and France.
Russia-Ukraine War: Key Things to Know
On the ground. Russian forces, battered by the local resistance, have stepped up their bombardment across Ukraine, targeting locations far from the front lines. Satellite imagery of a convoy north of Kyiv suggests that Russia is repositioning its forces for a renewed assault there.
“We expect them, the world leaders, to show how they can influence the situation,” he said. “How they can do a simple thing — free one person, a person who represents the entire Melitopol community, Ukrainians who do not give up.”
Melitopol lies only a short distance from Crimea, which Russia annexed in 2014. The city came under fierce assault on the first day of the war, Feb. 24, and Russian soldiers entered only days later. While the city fell, Mr. Fyodorov remained defiant.
“We are not cooperating with the Russians in any way,” he said.
As resistance has grown more brazen, the Russian tactics have grown more brutal, according to the Ukrainian government and witnesses. The General Staff of the Armed Forces of Ukraine said on Friday that Russian soldiers were committing robberies, taking hostages and executing civilians. The reports of executions and hostage taking could not be independently verified, but there have been multiple witness accounts, often recorded on video, of Russian soldiers looting stores and homes.