Mikhail Khodorkovsky spent Sunday being alternately cheered and heckled during a trip to the eastern Ukrainian city of Donetsk.
Khodorkovsky, the Russian ex-tycoon who spent 10 years in jail before his surprise release in December, visited the flashpoint city for what his spokesperson said was a fact-finding mission.
His first destination was the city's regional administration building, which has been held by pro-Russian separatists since early April.
Khodorkovsky had hoped to speak to the separatists but was roughly turned away
by supporters manning the barricades outside, who accused the former billionaire of "selling out" his country and urged him to get his news from Russian mass media rather than wasting the separatists' time.
The rebuff seemed to catch Khodorkovsky off guard, with his spokesperson noting a similar visit to Kharkiv a day earlier was far friendlier.
Still, some Donetsk residents were eager to meet with Khodorkovsky, who joined a number of Russian analysts for a press conference to answer questions from local journalists and activists.
Addressing the question of how to stop Russian President Vladimir Putin's aggression against Ukraine, Khodorkovsky said it was critical to convince Russia's intelligentsia to stop echoing Kremlin propaganda labeling Ukraine's new leadership as "fascists and Banderovtsy," a reference to World War II-era Ukrainian nationalist Stepan Bandera.
"Putin is a person who rarely -- actually, I think never -- goes against dominant public opinion," Khodorkovsky said. "If we manage to change Russian public opinion, it's the first step toward preventing something irreversible from happening."
Khodorkovsky, who participated in a conference in Kyiv last week, said he saw it as his "personal task" to help resolve Ukraine's future.
Jailed in 2003 on fraud and tax-evasion charges criticized as politically motivated, Khodorkovsky has resettled in Switzerland since his release from jail.