Anti-aircraft guns have been installed in three prisons housing suspects involved in the July 15 coup attempt blamed on a junta loyal to the Gülenist Terror Group (FETÖ). Authorities have also announced that security measures were increased in 387 prisons across the country after the putsch attempt that led to the arrest of thousands of military officers and non-military FETÖ figures.

The disclosure comes after several media reports suggested that FETÖ suspects were planning a mass prison break. Among the prisons where anti-aircraft guns were deployed are the Silivri prison located in Istanbul, the Sincan prison in the capital Ankara and the Şakran prison in the western city of İzmir.

Enis Yavuz Yıldırım, head of the General Directorate of Prisons and Detention Houses, overseeing the prisons, told Anadolu Agency that they were "in full control" of prisons against "internal and external threats."

Since the coup attempt, that left more than 240 people dead, authorities have arrested some 37,000 suspects on charges of taking part in the coup and being a member of the terrorist group, FETÖ. Earlier this month, Turkish media outlets had reported that a plot to escape prison by FETÖ suspects was discovered by the Sincan prison administration. Blueprints of the prison and encrypted notes indicating a prison break were found in the possession of inmates who were also accused of planning riots and taking prison guards hostage to facilitate the escape of more than 5,000 people.

The security of the prisons was increased over concerns that suspects linked to FETÖ may plot an escape, while a large number of prison guards and administrators suspected of having links to the terror cult were dismissed. The number of prison guards was increased and permission to walk in the prison courtyard was changed, creating a system where an inmate can only take a courtyard break with the same partner inmate, preventing the interaction among prisoners held in solitary confinement. Additionally, police officers will back up gendarmerie officers tasked with prisoner transfers in a measure to prevent the escape of inmates during transfers between prisons,

Yıldırım stated that they were planning to hire an additional 7,500 security personnel for prisons across Turkey by the end of the year in order to boost capacity. Turkey's prisons were already filled beyond their capacity before the coup attempt, whose aftermath saw a surge in arrests and detentions targeting the Gülenist terror cult.