A prisoner has been shot dead while trying to escape from a jail in Iraq with two other ISIS inmates, the country's security forces have said. The three men, all members of the extremist group, were serving life sentences at a jail in Taji, north of Baghdad. They were spotted as they climbed an external wall and guards opened fire "when they refused to heed warnings", the security forces said, adding that one prisoner was killed. The remaining two surrendered. Security sources did not identify the three men. An investigation commission has been formed to interrogate the remaining two prisoners, a security official said. ISIS swept across parts of Iraq and neighbouring Syria in 2014 where they set up a so-called caliphate. Jail breaks were a key part of ISIS's strategy at the time to rebuild their ranks, after losing many members during the US-led occupation. About 100 inmates were taken from a prison in Tikrit in 2012, while a much bigger jail break in two prisons —Taji and Abu Ghraib, in July 2013, which involved car bombs used to destroy prison walls, freed as many as 500 fighters. Most of those freed at the time are likely dead or recaptured and Iraq has since relocated high risk prisoners to desert complexes in the far south of the country. Iraq officially declared victory over ISIS in 2017, and two years later the group was defeated in Syria. But sleeper cells continue to be active in both countries and frequently carry out attacks. After the demise of ISIS in Iraq, courts in the country have sentenced hundreds of members to death for crimes committed by the extremists. Only a small proportion of these sentences have been carried out, because they must be approved by Iraq's President, Barham Salih. Mr Salih, who has held the post since 2018, is known to be against capital punishment.