Hardened criminal Alket Rizai was holding two prison guards hostage at Malandrino Prison in central Greece on Saturday night.
It appears that Rizai was attempting to break out of jail with two fellow inmates. He is said to be armed with sharp implements.
A prosecutor has arrived at the prison and police have begun negotiations.
Rizai, an Albanian national, was an associate of notorious fugitive and notorious criminal Vassilis Palaiocostas with whom he escaped from prison twice.