KIEV - The Ukrainian authorities on Wednesday have freed two captured Russian citizens as a part of an apparent prisoner swap with Moscow, which also saw a release of the Ukrainian army pilot Nadiya Savchenko from jail in Russia.

The press service of the Ukrainian President Petro Poroshenko said that the head of the state has signed a decree to pardon detained Russian citizens, Alexandr Alexandrov and Eugene Yerofeev, prior to their release.

In parallel, the Kremlin issued a statement saying that Russian President Vladimir Putin has granted pardon to Savchenko.

Earlier in the day, Savchenko, who was imprisoned in Russia for almost two years, has returned to Kiev, while Alexandrov and Yerofeev flew to Moscow.

According to Ukrainian media, an agreement on prisoner swap was reached on Monday during the phone talks in the Normandy format between Poroshenko, Putin, French President Francois Hollande and German Chancellor Angela Merkel.

Some political experts here have suggested that the prisoner exchange could become a first step towards warming up in relations between Kiev and Moscow, which have been deteriorating since early 2014 over different stances on the developments in Crimea and eastern Ukraine.

In 2016, a Russian court has sentenced Savchenko for 22 years behind the bars, after founding her guilty of complicity in killing civilians, including two Russian journalists, during the conflict in eastern Ukraine.

The pilot has denied the charges and said she had been kidnapped in Ukraine and then handed over to Russian authorities.

In May 2015, Ukrainian security officers seized Alexandrov and Yerofeev, who claimed to be Russian soldiers, while fighting in Ukraine's conflict-torn Lugansk region.

The Russian Defense Ministry said that the two men captured by the Ukrainian forces had previously served in the Russian army, but had been no longer active servicemen when they were detained.