Security forces have retaken control of a prison in western Indonesia following a riot.

A spokeswoman for the Correctional Directorate, Rika Apriyanti, says angry inmates set fire to Langkat prison in North Sumatra province, which is designed to house 900 prisoners but now has more than 1,600.

She said on Thursday the cause of anger is still being investigated. Local media reports said the riot began when inmates protested improper treatment by a guard of an inmate. Other inmates joined the protest and it turned violent.

Several fire trucks were mobilized to extinguish the fire and hundreds of police and soldiers were deployed around the prison to prevent inmates from escaping.

Riots and jailbreaks are common in Indonesian prisons, which are often overcrowded.