Sialang Bungkuk escape, Indonesia
A villager (L) living near the prison and riot police with rifles stand guard in front of Sialang Bungkuk jail after about 200 prisoners broke out of the facility in Pekanbaru on Indonesia's Sumatra island on 5 May 2017Antara Foto/Rony Muharrman via Reuters

A massive search operation is underway on the Indonesian island of Sumatra after an estimated 200 prisoners broke free from an overcrowded facility on Friday (5 May).

The incident took place at the Sialang Bungkuk prison located in Pekanbaru, Riau province as inmates were allowed out of their cells to take part in prayers in the Muslim-majority country, officials said. At first prisoners attempted to break through the main door of the jail.

However when that failed, they managed to flee through a side entrance to the facility, Agence France-Presse (AFP) reported.

According to reports, a handful of prisoners were swiftly recaptured. "About 200 escaped, but at least 77 people have been recaptured," local police spokesman Guntur Aryo Tejo told AFP.

Television stations broadcast footage of the incident as dozens of prisoners ran free. As officials pursued the inmates, a police officer dressed in black riot gear was seen holding a man in a headlock.

Police installed road blocks around the city as a huge manhunt was launched.

The male-only facility is designed to hold 300 prisoners, but was housing 1,870 inmates with just five guards and a porter on duty at any given time, Indonesia's director general of prisons, I Wayan Dusak, said.

The official added that inmates are unhappy with the head guard, who they want replaced. More than 1,000 inmates who did not break free are reportedly refusing to return to their cells unless the top guard is replaced amid reports of harsh treatment.

Ferdinan Siagian, head of the Law and Human Rights Ministry's Pekanbaru office, told the Jakarta Post: "Information we received says several prison officers had often triggered conflicts with prisoners, so they decided to flee via several doors in the prison that were open during the Friday prayer."

More than 400 police and military personnel have been dispatched to guard the prison as efforts to track down the missing prisoners continue.