MOSCOW — Russia and Ukraine began a long-anticipated swap of dozens of prisoners on Saturday, with government planes taking off from both countries’ capitals around the same time, a significant step toward defusing tensions between the two nations.
A plane carrying 24 Ukrainian sailors detained by Russia in the Kerch Strait last year took off from Vnukovo Airport near Moscow, according to Ukraine’s presidency and Nikolai Polozov, a lawyer working on their case in Russia, who announced the news on the Ukrainian television channel 112.
A similar plane departed from Borispol Airport near Kiev, taking off around noon local time.
Oleg Sentsov, a Ukrainian filmmaker who had been sentenced to 20 years in prison in Russia on terrorism charges, was also included the prisoner exchange, his lawyer Mark Feigin said on Twitter. Ten other prominent Ukrainians held by Russia were expected to be part of the swap, he added.
The Russian Embassy in Kiev posted a picture on Twitter of the released Russians, writing: “Our people have been released! They are flying home.”
The swap of prisoners, believed to be dozens on both sides, appeared aimed at resolving a long-running conflict between Russia and Ukraine. It was likely to be seen as a diplomatic victory both for President Vladimir V. Putin of Russia and for Vladimir A. Zelensky, who ascended to the Ukranian presidency after winning national elections in May.
For Mr. Putin, the exchange could open the door to easing tensions with Europe, which imposed sanctions on Russia’s ailing economy after the annexation of Crimea in 2014. For the Russian leader — weakened by an ailing economy and weeks of protests calling for fair municipal elections after opposition candidates were stricken from ballots — the gesture could be seen as a way to demonstrate to Europe that he was willing to compromise.
For Mr. Zelensky, the swap represented the first diplomatic coup of his presidency and the first significant campaign promise fulfilled. With his approval ratings at record-high levels, it is important for Mr. Zelensky to keep his administration’s momentum and to deliver results. Defusing tensions in the country’s east was the top priority for Ukrainians, polls showed.
The governments in Kiev and Moscow have been locked in diplomatic clashes since Russia seized Crimea, and armed Russia-backed separatists have waged a deadly struggle in Ukraine’s east. More than 13,000 people have been killed during the conflict, a quarter of them civilians, according to the United Nations.
Ukraine’s president at the time of the sailors’ detention, Petro O. Poroshenko, had put his nation on a war footing with Russia as tensions over the shared Kerch waterway escalated into a crisis that dragged in NATO and the United Nations.
The sailors, who were onboard three small vessels, had been involved in a clash with a Russian tanker in the strait, a disputed waterway linked to the Black Sea. Some of them were wounded in a firefight.
In July this year, Ukraine seized the Russian tanker that it said was used during the confrontation. The tanker was accused of blockading the route under the Kerch Bridge, a structure built hastily and opened by President Vladimir V. Putin of Russia in 2018, as the first direct link from Russia to the Crimean peninsula.
Both planes had landed by Saturday afternoon, and the prisoners were greeted by their families in Kiev, according to footage broadcast by Ukrainian television stations.
President Zelensky greeted the prisoners at the airport. Standing near the plane, he said at a news conference: “On Aug. 7, we had a telephone conversation with Russian President Vladimir Putin. We have agreed on the first stage to unblock our dialogue and on the first step to stop the war: the release of our servicemen, our hostages, our sailors, our territories.”
He added: “We agreed that we should work hard for a month without any lies and return our boys home. We agreed to release sailors and prisoners of war. I believe that the first step has been fulfilled.”
Mr. Zelensky said that the two counties would aim to “ return all our hostages.”
Widespread reports of a prisoner exchange had been rumored for some time, and last week, when Ukraine’s chief prosecutor said on Facebook that it was underway, relatives of the detained sailors flocked to the Kiev airport.
Their hopes were dashed when Ukraine’s presidency said that the exchange was not taking place.
Mr. Sentsov, detained in Crimea in 2014, had been accused of plotting to blow up bridges, power lines and a statue of Lenin. He denied plotting those actions but admitted opposing Russia’s takeover of Crimea. He was given a 20-year prison sentence in a penal colony in Siberia.
His imprisonment attracted international support and created an unwanted backdrop for Moscow as the men’s soccer World Cup got underway in 2018. That summer, he went on a hunger strike and was kept alive for 145 days by medical intervention.
Reports of a prisoner swap began to emerge when he was moved from his Arctic prison last month to one in Moscow.