Ukrainian President Volodymyr Zelensky proposed direct talks with Russian President Vladimir Putin, as his American diplomatic backing unraveled in the impeachment scandal.

As the formal peace process for the Ukraine war bogged down last month, the country's president, Volodymyr Zelensky, reached out for a direct meeting with President Vladimir V. Putin of Russia, an intermediary in the talks revealed on Tuesday, according to The New York Times.

The United States does not participate directly in the negotiations, which are overseen by France and Germany. But Mr. Zelensky had pressed for a more robust American role, in part by seeking a meeting with President Trump in the White House.

That effort became entangled in a request for political favors in exchange for the White House meeting – a request that is now a focus of the impeachment inquiry in the House of Representatives. There has been no sign of United States pressure on Russia to sit down for the peace talks, and since September, five American officials who dealt with Ukraine have resigned.

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With the negotiations delayed, Mr. Zelensky in late October offered a direct meeting, a former president of Kazakhstan, Nursultan Nazarbayev, said on Tuesday. Mr. Nazarbayev, who is acting as an intermediary, said he had conveyed the offer to Mr. Putin.

"I think we need a separate, personal meeting of the presidents of Russia and Ukraine," Mr. Nazarbayev said at a policy conference in Kazakhstan.

Most analysts say Russia, which arms and supports the separatist rebels who control parts of eastern Ukraine, wants changes to Ukraine's domestic political system that would give Moscow a greater say over the country's affairs.

The Kremlin's response on Tuesday was lukewarm. Mr. Putin's spokesman, Dmitri Peskov, suggested in a conference call with reporters that the Russian leader would not immediately accept. Mr. Putin would not hold "a meeting just for the sake of a meeting," he said.

Mr. Zelensky ran on a promise to negotiate an end to the war. One tactic was an effort to maneuver Russia into negotiations that would recognize the Kremlin as a party to the conflict; one-on-one talks with Mr. Putin would signal a Russian role in the war.

The Kremlin has delayed the French- and German-led talks as it demanded ever more concessions. Mr. Zelensky agreed to a Russian-approved political formula for settlement and withdrew troops from the front in some locations – even pulling back some troops under fire, something he had said he would not do.

"He keeps rising the price, because he sees that Zelensky is interested," John E. Herbst, a former U.S. ambassador to Ukraine, said of Mr. Putin. "There are limits to the price Zelensky is willing to pay."

One limit is domestic opposition. Concessions are inflaming certain forces who deride his policies as capitulation.

Some Russians also see the concessions as signs of weakness from a Ukrainian president whose hopes for American support have evaporated.

Mr. Putin "is not saying directly that Ukraine will have to negotiate because it lost support in the West," Konstantin B. Gaaze, a politics professor at the Moscow School of Social and Economic Science, said in a telephone interview. "But he could say that."