Who are the Russian "volunteers" serving with pro-Russian rebel forces in eastern Ukraine? The BBC's Olga Ivshina obtained a rare interview with a Russian special forces soldier, who described the key role played by Russian troops in recent fighting.
Russia's War Against Ukraine
BBC: How Ukraine rebels rely on Russians
A pro-Russia rebel and an International observer of the Organization for Security and Co-operation in Europe (OSCE) stand next a destoyed car after shelling during an OSCE inspection tour near the village of Shirokino, near the eastern Ukrainian port city Mariupol.
