Ukrainian government troops have briefly recaptured the rebel-held city hall in Mariupol, before quickly abandoning it. Separatists then retook the building.
A week of violence, which has seen more than 40 people killed in clashes that ended with pro-Russian demonstrators trapped inside a building, has hardened positions and spread the unrest.
Ukrainian presidential candidate Petro Poroshenko said: “For those who do not understand neither Ukrainian nor Russian, no German, no English, we should find out the language they understand. For those people who [are] keeping the machine gun, for those people who [are] killing the people, for those people who are terrorists – we should find out the right language they understand and that would be the language of force.”
Meanwhile in the rebel stronghold of Slavyansk, around two hundred people gathered to pay their respects to 30-year-old teacher Irina Boevets who was shot dead on Monday.
Locals say she was killed by a Ukrainian sniper.
Olga Tigunova, a friend of Irina, explained: “She stepped onto her balcony and waved at her husband who was nearly home. She was about to go back inside when a bullet hit her temple and went through her head.”
Meanwhile Pavel Gubarev, the self-declared People’s Governor of Donetsk Region, has been released with others in exchange for three Ukrainian special forces officers.
A spokesman at the separatists’ headquarters in Slavyansk said, “it was a swap of hostages for prisoners of war.”