Kiev: Ukranian police successfully freed hostages after a man believed to be strapped with explosives held nine adults and two children in a post office in the Ukrainian city of Kharkiv on Saturday.

Police arrested the hostage-taker after an hours-long standoff.

The man in the post office was concerned about the recent prisoner exchange between the Ukrainian authorities and pro-Russian separatists and thought more prisoners should have been released, police said. Credit:EFREM LUKATSKY

"All hostages freed in Kharkiv. The assailant was arrested," President Petro Poroshenko wrote on Twitter, while Interior Minister Arsen Avakov published a picture of the man, with blood streaming down his face, being held by a policeman.

None of the hostages were harmed. A Reuters witness at the scene saw special force police in green camouflage rushing to the entrance of the post office, a yellow-and-white building at a road junction in the northeastern city near the Russian border.