Conflicting reports emerged about dozens of deaths at Aleppo’s central prison on Friday.

Forces loyal to Syrian President Bashar Assad on Friday executed 50 prisoners the jail, the rebel-affiliated Local Coordinating Committees organization said.

The opposition group Syrian Observatory for Human Rights confirmed late Friday that reports had arrived from inmates in the prison saying that 31 other inmates were killed — not by Assad’s troops, however, but by rebel shelling on the prison in an attempt to liberate it.

According to this report, 40 government troops were also killed in the offensive on the prison, which is believed to hold hundreds of regime opponents.

The dead were said to have been buried in the prison’s yard.

Rebels aiming to topple Assad began to focus on the prison — the major jail in Aleppo — in May after detonating two car bombs outside the facility in April. At first, they tried to storm it, then began to lay siege to it.