Hennadiy Afanasyev / Facebook Ernest Mezak

"There is an agreement in principle on the transfer of Afanasyev and Soloshenko. And Poroshenko has confirmed this. However, the conditions and mechanisms of the transfer are now being discussed," RIA Novosti quoted Afanasyev's lawyer Alexander Popkov as saying.

Yuriy Soloshenko / Screenshot

Both Soloshenko and Afanasyev wrote a petition for a pardon to the President of Russia, and most likely, their transfer to Ukraine will be based on this mechanism, Popkov said.

"Both have health issues. Russia is interested in their transfer, and Ukraine wants to quickly take them back," Popkov said, noting that he is not willing to disclose the details, so as not to disrupt the talks.

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Earlier, Ukrainian President Petro Poroshenko said that he had agreed with Russia on the return of Afanasyev and Soloshenko to Ukraine.

At the same time, on Monday, May 30, Kremlin spokesman Dmitry Peskov did not confirm reports on an alleged agreement with Kyiv on handing over Soloshenko and Afanasyev, according to Russian news agency TASS.

"I could not confirm this," Peskov said. "I have no information that would allow me to confirm this," he added.

A 24-year-old lawyer and photographer Afanasyev was sentenced by the Russian court to seven years in a penal colony.

Read alsoKlimkin: Ukraine negotiating swap of Ukrainians jailed in Russia for captive Russian soldiersIn March-April 2014, Afanasyev attended rallies and meetings of supporters of a unified Ukraine, participated in the organization of first aid trainings. After the occupation of Crimea, he was detained by the Russian Federal Security Service (FSB), being accused of allegedly entering a terrorist cell organized by Oleh Sentsov. He was also charged with participation in an arson attack on Simferopol offices of the Russian Community of Crimea and the United Russia Party. What is more, he was accused of allegedly coordinating Oleksiy Chyrniy in manufacturing explosives for the destruction of a monument to Lenin.

On August 5, 2015, the Russian court sentenced a 73-year-old Ukrainian "spy" Yuriy Soloshenko to six years in a penal colony.

Former director of Ukraine's Poltava-based Znamya defense plant Yuriy Soloshenko was arrested in Moscow in August 2014. He arrived in Moscow on a business trip. But the FSB decided that Soloshenko had tried to illegally acquire secret components for S-300 anti-aircraft missile systems for the Ukrainian defense industry.