More than 2,000 Pro-Russian insurgents laid siege to the police headquarters in Odessa in southern Ukraine, forcing police to release several people who were detained for last Friday’s deadly violence in which 42 people were killed.

It started as a peaceful protest, but quickly escalated.  Some wore masks as they used improvised weapons and rocks to break the windows on the building, as a crowd chanted “Fascists, fascists” at the police, as well as pro-Russian slogans.  Police at first released one of the detainees, but eventually freed dozens.  One news source said 30 were let go, while the Interior Ministry put that number at 67.

On Friday, the tension between encampments of pro-Kiev and pro-Moscow demonstrators boiled over as residents ripped up the cobblestones of their own city to throw at each other.  Shots rang out from the Russian side, and a group of separatists fled the crowd and tried to take shelter in the Trade Unions building.  Pro-Kiev demonstrators threw Molotov Cocktails at the barricaded separatists.  30 people were killed by smoke inhalation, eight more died leaping out windows to try and escape.

Ukraine Prime Minister Arseniy Yatsenyuk visited Odessa on Sunday, and blamed the deaths on what he called “inefficient” police.  But he added that the unrest was “part of a plan fomented by Russia to destroy Ukraine”.

“Russia’s aim was to repeat in Odessa what is happening in the east of the country,” Yatsenyuk said.