Indonesian authorities have said about 200 inmates remain at large two days after a mass escape from an overcrowded prison on Sumatra island.

The breakout at Sialang Bungkuk prison in Pekanbaru on Friday occurred when prisoners were let out of their cells to perform prayers. They broke through a prison door, overwhelming the few guards on duty.

Police said 242 men had been recaptured by Sunday morning, leaving about 200 still at large.

Authorities were initially uncertain how many prisoners had escaped, estimating the numbers at between 100 and 300.

Police said some of the men surrendered or were returned by their families and others were captured by local residents, police and soldiers.

Various officials have said the prisoners were angry about poor conditions and treatment. The prison has a capacity of about 360 but was holding more than 1,870 men, according to a local police spokesman, Guntur Aryo Tejo.

Tejo said four of the escaped inmates were apprehended by police late on Friday about 60 miles from the prison, on a bus heading for West Sumatra province.

Hundreds of police and soldiers have been deployed in the hunt for the prisoners.

Jailbreaks are common in Indonesia, where overcrowding has become a significant problem in prisons that are struggling to cope with poor funding and an influx of people arrested under a “war on drugs”.

Friday’s escape was the biggest since July 2013 when about 240 prisoners, including several convicted terrorists, escaped after a deadly riot at a prison in Medan, the capital of North Sumatra province.