(Updates with sources saying final destination Lithuania, background)
By Jack Stubbs
KIEV, Feb 2 (Reuters) - Dmytro Bulatov, a Ukrainian activist whose torture at the hands of kidnappers outraged anti-government protesters, is flying out for treatment in Lithuania on Sunday after officials in Kiev dropped charges against him, allies and diplomats said.
Opposition leader Vitaly Klitschko told Reuters at the Kiev clinic where Bulatov had been since Thursday that the activist was flying to the Latvian capital Riga. An aide to Klitschko said he would go on from there to neighbouring Lithuania.
Diplomatic sources said he would be treated in Lithuania after European Union leaders, who oppose President Viktor Yanukovich, had offered to ensure Bulatov was cared for.
Opposition leaders, medical staff and diplomats have been involved in efforts to thwart police attempts to arrest the activist in hospital. Klitschko said the Interior Ministry had assured him that Bulatov was now free to leave the country.
Police have said they wanted to place Bulatov, 35, under arrest on a charge of taking part in "mass disorder" related to protests consisting of convoys of cars driving up to the homes of allies of Yanukovich.
Another opposition politician, parliamentarian and business magnate Petro Poroshenko, was quoted by Ukrainian media saying that a Kiev court had quashed the case against Bulatov on Sunday. On Facebook, Poroshenko said he had taken off for Riga.
European Union leaders, notably Germany's foreign minister, offered Bulatov treatment after he was found bloodied and injured in woods outside the capital. He said unidentified assailants had driven nails through his hands during a "crucifixion" and beat him during a week in captivity.
Video of his bloodied face has been replayed repeatedly on opposition television channels, fuelling anger at Yanukovich among protesters occupying main streets and public buildings in Kiev and elsewhere and demanding a change of leadership.
Yanukovich sparked the protests in November when he spurned a trade pact with the European Union and turned instead to Ukraine's old master Moscow for financial support. (Additional reporting by Richard Balmforth and Natalia Zinets; Writing by Alastair Macdonald; Editing by Kevin Liffey)