PARIS — Russian President Vladimir Putin and Ukraine’s Volodymyr Zelensky agreed to a renewed cease-fire and to exchange all known prisoners when they met for the first time in Paris on Monday, making modest gains in peace talks designed to end a deadly war in eastern Ukraine.

It was the first effort in three years to wind back a bitter war that has cost 13,000 lives and resulted in the loss of Ukrainian territory to separatists backed by Moscow.

“We have said once again how important it is to have a dialogue between parties,” Putin said.

Zelensky said the meeting itself was “a big step toward peace.”

The talks yielded enough progress to get the peace process moving, but as expected, there was no major breakthrough.

“We haven’t found the magic wand, but we have relaunched talks,” said French President Emmanuel Macron, who convened the gathering. He said the talks had made “practical, tangible progress.”

The parties agreed to meet again in four months to discuss one of the stumbling blocks: conditions for elections in eastern Ukraine, which would then lead to special status for the regions.

The Ukrainian president has declared that there can be no elections in those regions until all military formations have withdrawn.

The negotiations — pitting a comedian turned president with no international diplomacy experience against a calculating former KGB agent who has been in power for decades — come at a crucial moment in Ukraine’s grinding conflict in the east.

Civilians and soldiers are still dying along the front lines, and Zelensky rose to power on the promise of delivering peace. But some observers fear he could be pushed into concessions that would further embolden Putin.

This is a lonely moment for Zelensky. Once-ironclad U.S. support for Ukraine is shrinking under President Trump. German Chancellor Angela Merkel helped mediate Monday’s meetings, but she is distracted by her own roiling domestic politics.

And Macron, who has tried to cast himself as the leader of Europe, has championed a reset with Russia, declaring that even though he has “no illusions” about the Kremlin’s conduct, it is not an enemy.

Russia is under U.S. and European sanctions for its actions against Ukraine, including its annexation of Crimea in early 2014 and its military support for separatists who carved off a chunk of eastern Ukraine. But Macron’s call for a rapprochement suggests that European support for sanctions will not last indefinitely.

The Normandy Format talks on Monday involved a series of meetings. Merkel and Zelensky arrived at the French presidential residence, the Elysee Palace, about 3 p.m. Putin arrived about 15 minutes later. Zelensky first met with Macron and then Merkel. After a meeting of all four leaders, Putin and Zelensky held a one-on-one session, according to Elysee officials, which was followed by an official dinner.

Emmanuel Macron, Angela Merkel, Volodymyr Zelensky and Vladimir Putin met in Paris on Dec. 9 for talks to end Ukraine’s war. (Reuters)

Tass, the state-owned Russian news agency, reported that the two had a 10- or 15-minute one-on-one meeting after an hour-long session that included the Russian and Ukrainian leaders and their delegations.

Interfax reported that Russia and Ukraine also discussed but failed to reach agreement on the renewal of a gas transit deal involving Russian gas piped via Ukraine to Europe. Transit fees on Russian gas are crucial to Ukraine, worth about $3 billion a year to its budget.

Ukraine and Russia have accused each other of violating previous cease-fires.

Zelensky said he wanted a genuine, lasting cease-fire with clear obligations on both sides, not a “fake” one, where shooting started again after a few days. “A serious cease-fire means not shooting, as I understand it, one with clear terms and obligations.”

He urged Russia to exert its influence and added: “I am convinced we will see a cease-fire by the end of this year.”

The parties also agreed to set up three more zones of disengagement on the front lines of the conflict.

The obstacles to further progress are formidable.

Taras Semenuk, an analyst with the independent KyivStart think tank, said in an interview that if Zelensky reached agreement with Putin, his political opponents would portray him as betraying Ukraine’s interests.

“It doesn’t matter what kind of solution it will be. The opposition is already preparing arguments to criticize the president. It is possible these arguments will translate into protests in the streets of Kyiv,” he said.

Putin, meanwhile, is seen as unlikely to give up Russia’s long-term strategic objective of keeping Ukraine firmly in its geopolitical backyard, rather than see it pivot further to the West and join NATO.

Officially, Russia denies military involvement in the eastern Ukraine conflict and calls it an internal Ukrainian matter.

Sergey Korsunsky, a Ukrainian official from the diplomatic academy of the Ministry of International Affairs, said in an interview that the talks offered Zelensky “a moment of truth” and his first chance to evaluate whether Putin was willing to reach a peace deal.

Korsunsky said everything would depend on Putin. “Putin will make a decision. We need to understand this [decision] in order to make a decision ourselves. If there are conditions that we cannot implement, then we will search for another way.”

Delivering peace was Zelensky’s biggest campaign promise in his upset April victory against Petro Poroshenko, the man who led Ukraine since close to the start of the 2014 conflict.

But some Ukrainians fear that Zelensky will make too many compromises with Putin, either because of a lack of support from the West or because of his own lack of experience in difficult international negotiations.

In Ukraine, many observers — even Zelensky’s supporters — were nervous about the meeting at a moment when prominent Republicans in Washington have seized on the false conspiracy theory that Ukraine, not Russia, interfered in the 2016 presidential election.

“The people in the Kremlin should order boxes of champagne. Even people from the GOP are saying maybe Ukraine meddled in the 2016 election,” said Pavlo Klimkin, Ukraine’s foreign minister until August.

On the eve of the talks, Zelensky’s political opponents rallied in Kyiv, warning that the Ukrainian president should not surrender to Putin.

Poroshenko, whose relations with Putin were poisonous, told the rally no good could come of the talks.

“Don’t trust Putin. Never. At all. Putin manipulates with everything: content, facts, numbers, maps, emotions. He hates Ukraine and Ukrainians and does not see our place on the political map of Europe,” Poroshenko said.

Mykhailo Onipchenko, a business executive, said in an interview that he doubted Zelensky would succeed, “but at least he will better understand who Putin is.

“Ukraine’s goal is to become free and to restore unity, and Putin’s goal is to destroy our liberty and sovereignty. And Zelensky doesn’t understand that it will be like a sheep negotiating with the wolf,” he said, describing the talks.

Ukraine’s minister for economic development, Tymofiy Mylovanov, said Monday that Russian aggression against Ukraine had cost the smaller nation’s economy between $50 billion and $150 billion since Russia annexed Crimea.

The International Monetary Fund announced Saturday that a provisional agreement had been reached with Ukraine for a three-year, $5.5 billion loan — although the deal has not been approved by IMF management or its board. Ukraine would have to implement “a set of prior actions,” according to a statement Saturday by IMF Managing Director Kristalina Georgieva. She said Ukraine needed to strengthen the rule of law, improve judges’ integrity and curb the role of powerful vested interests.

Trump’s suspicions of Ukraine and his role in the holdup of military aid this past summer have cast doubts on U.S. support for Ukraine in its conflict with Russia.

Zelensky’s allies say U.S. backing remains crucial in discussions with Russia.

“We are engaged in negotiations on the weaker side. And that U.S. support is part of the leverage we have,” said Bohdan Yaremenko, chairman of the foreign affairs committee of the Ukrainian parliament and a Zelensky ally.

Trump is facing impeachment proceedings because of a July 25 phone call in which he asked Zelensky to dig up dirt on a domestic political opponent at a time when the White House had frozen nearly $400 million in military aid to Ukraine.

Trump has denied wrongdoing, insisting the phone call was “perfect,” and Zelensky has repeatedly stated that there was no quid pro quo in the July conversation, nor any pressure.

The talks in Paris came at one of the most contentious moments of Macron’s presidency, as France has been crippled by transportation strikes in response to his plans to overhaul the country’s retirement system. The foreign heads of state all arrived in a city on edge, where public transportation isn’t operating normally and where a massive demonstration is set for Tuesday.

Birnbaum reported from Kyiv, and Natalie Gryvnyak in Kyiv contributed to this report.