* Activist says suffered "crucifixion", beaten in captivity
* Leaves Ukraine after authorities drop charges against him (Adds airport arrival, Poroshenko quote, charges, flight details)
By Jack Stubbs
KIEV, Feb 2 (Reuters) - Dmytro Bulatov, a Ukrainian activist whose torture at the hands of kidnappers outraged anti-government protesters, flew 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 Vilnius via the Latvian capital Riga.
Arriving in an ambulance convoy accompanied by his wife, Bulatov was met at Kiev's Boryspil airport by Klitschko and another senior opposition figure, Petro Poroshenko.
"We saved a life today," Poroshenko told Reuters. "We will do it for everybody who is arrested and detained."
Diplomatic sources said Bulatov, 35, would be treated in Lithuania after European Union leaders, who oppose President Viktor Yanukovich, had offered to ensure he was cared for.
Opposition leaders, medical staff and diplomats had 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 under arrest on a charge of taking part in "mass disorder" related to protests consisting of convoys of sometimes hundreds of cars driving up to the homes of allies of Yanukovich.
The Ukrainian Interior Ministry said on Sunday it had not dropped charges against the activist, but Deputy Prosecutor General Liliya Frolova was quoted by Interfax news agency saying there were no obstacles to him leaving the country.
Having taken a commercial flight to the Baltic republic of Latvia, Bulatov was expected to continue later on Sunday to neighbouring Lithuania, the foreign ministry in Vilnius said.
EU 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 in a "crucifixion" and had beaten 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 across Ukraine and demanding a change of leadership.
Yanukovich sparked the protests in November when he spurned a trade pact with the 28-nation EU 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 Gareth Jones)