Viktor Medvedchuk, the head of Ukraine's pro-Kremlin Opposition Platform — For Life party, said in a televised news conference on June 28 that the four released prisoners are Eduard Mikheyev, Yakiv Veremeychyk, Dmytro Velykiy, and Maksym Horyayinov.
Three of the four Ukrainians are military servicemen, pro-Russian Ukrainian lawmaker Vadim Rabynovych said on Facebook. He didn't specify who the three were.
The four are scheduled to fly to Kyiv in the "near future," said Medvedchuk, whose eldest daughter has Russian President Vladimir Putin as her godfather.
The freed captives, who were transported from the Russian city of Rostov-on-Don to Minsk, were at Medvedchuk's side during the news conference.
Medvedchuk said that an agreement to release the men was reached after talks with Moscow-backed militants, who control about 3 percent of Ukrainian territory in the easternmost regions of Luhansk and Donetsk.
More than 13,000 people have been killed in the Donbas war zone since fighting broke out in April 2014, when an armed unit led by Igor Girkin, a former Russian Federal Security Service officer, took over the town of Slovyansk in the Donetsk region.
Two truces known as the Minsk accords — brokered in September 2014 and February 2015 — have contributed to a decrease in fighting but have failed to take hold.
More than 600 Ukrainian political and war prisoners are held in Russia, occupied Crimea, and in the non-government-controlled parts of the Donbas.
An additional 400 pro-Russian Ukrainian separatists are being held in Ukrainian prisons.
Ukrainian authorities say that between 2014 and 2018, 3,244 Ukrainian citizens were released from captivity on the territories controlled by Kremlin-backed militants.
