Egypt’s security chief announced Wednesday that he would dismiss hundreds of police officers for their role in the killings of more than 845 protesters during the country’s 18-day uprising last winter.

Minister of Interior Mansour el Essawi described the move, planned for mid-July, as the biggest purge of the police in Egypt’s history. His statement comes as tensions soar in the country over what many Egyptians feel is a lack of accountability for security and government officials involved in violence against protesters during the uprising that forced out President Hosni Mubarak.

The anger was apparent Wednesday as crowds in Suez attacked a police station after a Cairo criminal court rejected an appeal over the release on bail of 14 police officers charged with killing demonstrators.

A large rally is planned in Cairo on Friday to protest what activists say is a lack of justice for the “martyrs” of the revolution and the slow progress following Mubarak’s ouster.