Earthquakes that rocked Turkey and Syria on Monday damaged a prison in the Syrian town of Rajo, giving its 2,000 prisoners — about 1,300 of which are suspected Islamic State terrorists — an opportunity to riot. At least 20 reportedly escaped.

An official at the Rajo prison told AFP on Tuesday that inmates “started to mutiny and took control of parts of the prison” during the quakes. He said “about 20 prisoners fled,” and some or all are “believed to be ISIS militants.”

AFP consulted with the London-based Syrian Observatory for Human Rights, which said there was indeed a “mutiny” at the Rajo prison, although it could not confirm the escapes.

“The incident in Rajo comes on the heels of an IS attack in December on a security complex in their former de facto Syrian capital of Raqa, which aimed to free fellow jihadists from a prison there,” AFP noted.

The “Black Prison” of Rajo — so-called because of its gloomy interior and unsavory reputation — is controlled by pro-Turkish militia forces. In addition to the captive ISIS fighters, some of its inmates are members of Syrian Kurdish armed groups.

Local rumors claim ISIS commanders were ready to exploit the earthquake as an opportunity to free some of their fighters, and did so with the cooperation of corrupt prison officials. The UK Independent on Tuesday quoted a source who told the Syrian Observatory for Human Rights that the escapees paid the equivalent of one to ten thousand dollars in bribes for their freedom.