An ambulance took Dmytro Bulatov directly from the private clinic where he was being treated to the airport for a flight to Riga, and he is expected to travel on to neighbouring Lithuania for medical treatment.
His arrival at the airport just minutes before departure marked the culmination of an intense round of international diplomacy ever since he was found dazed and beaten in a village outside Kiev on Thursday.
The 35-year-old father of three said he was "crucified" by unidentified kidnappers who drove nails through his hands and cut off part of his ear while they held him for eight days following clashes in Kiev.
"They crucified me, nailed me, cut my ear off, cut my face," Bulatov said on Channel 5 television shortly after his release in his only public comments so far.
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"I can't see well now, because I sat in darkness the whole time," said Bulatov, his face swollen and caked in blood, which could also be seen covering his clothes.
The United Nations and the United States also voiced concern and Germany and Lithuania both offered him medical assistance.
"He will be brought by ambulance to hospital in Vilnius," Lithuanian Health Minister Vytenis Andriukatis told AFP yesterday.
"We are ready to help all injured Ukrainians, and we do not separate them into opposition and others in this case," he said.
Ukrainian Foreign Minister Leonid Kozhara on Saturday dismissed Bulatov's account and said his injuries were just "a scratch", but the ministry retracted the comments saying they wished him a "speedy recovery".
Over the last few days, protesters outside Bulatov's clinic physically prevented police from entering with a formal order for Bulatov to appear in court on charges of "organising mass disorder" in Kiev.
He faces up to 10 years in prison if convicted.