Scores of juvenile inmates, including killers and rapists, staged a mass breakout from a detention centre in eastern India after cutting through metal windows and gates, police said on Monday.

Thirty-four out of 86 inmates broke out of the facility in the Munger district of Bihar state on Sunday, an officer said. Twelve returned in the hours after the daring escape.

“The inmates broke the iron grills and the metal gate and fled in an overnight escape,” Ashish Bharti, Munger police chief, told AFP.

Many of the escapees have either been convicted or are awaiting trial for serious offences such as murder, rape and theft, the officer added.

Police are investigating the breakout and a manhunt is underway for the escapees.

Nearly 100 inmates fled a similar facility in the northern state in 2015 after tying bedsheets and scaling walls. About 31,000 offenders below the age of 18 are kept in juvenile homes intended for reforming the delinquents, according to official statistics.

The homes have no armed guards and inmates often sleep in dormitories instead of individual cells.

Young offenders have come under increased scrutiny after one the six accused in the brutal gang rape of a Delhi woman in 2012 was found to be a juvenile.