Eight Palestinian security prisoners in Israel’s Gilboa Prison in the Galilee are suspected of having tried to escape via a tunnel dug under their shared bathroom.

Guards from the Israel Prison Service, acting on intelligence, uncovered the shaft, the Prisons Service said Sunday.

The eight are members of Palestinian Islamic Jihad and were sharing the cell. Two of them are serving life sentences, a third is serving 25 years and the rest are detained until the completion of judicial procedures or serving sentences of up to two years, according to Ynet,

Authorities are still unsure of the tunnel’s depth and direction, and are still searching the adjacent cells. Pictures of the tunnel showed it leading from a cell toilet.

Commissioner of the Prison Service Aharon Franco said the discovery of the tunnel was a result of ongoing, intense activity aimed at thwarting prison breaks and that this was the second such tunnel uncovered over the past few months.

The Prisons Service is verifying where the prisoners disposed of the earth dug to make way for the tunnel.

In June, a similar tunnel was found in Shita Prison, also in northern Israel, from which a suspected escape by security prisoners was planned. The suspects had stashed uniforms worn by Prisons Service guards in the tunnel.