Three men fled Saturday evening from the Orsainville Detention Centre in suburban Quebec City with the help of a green-coloured helicopter, Quebec provincial police said.
Audrey-Anne Bilodeau, a police spokeswoman, said the helicopter flew west from the provincial detention centre, perhaps toward Montreal.
"We (are working with) a few partners like the airports of Quebec City and surrounding areas, the military bases and, of course, there's a ground search in the event that the helicopter is located," Bilodeau said late Saturday.
Provincial police Sergeant Ann Mathieu said the chopper put down in a courtyard of the detention centre then quickly took off again heading west.
Mathieu, however, said police were reluctant to reveal much else about their investigation for fear the escapees could be monitoring media reports.
The escapees were identified as Yves Denis, 35, Denis Lefebvre, 53, and Serge Pomerleau, 49.
The three men were being held at the detention centre waiting to stand trial, it was not immediately clear what charges they were facing.
Police released photos of the three men on social media and appealed to the public for help, but warned anyone who spotted them not to approach and immediately contact police.
The Orsainville Detention Centre, about 10 kilometres from the centre of Quebec City, can hold up to 710 offenders.
In 2010, it was the scene of a fire and a violent skirmish that ended with two inmates dead and another six rushed to hospital.
It was also the scene of a riot in February 2008, which was apparently triggered by a smoking ban at the facility.
Saturday's helicopter escape had similarities to another bold jailbreak last year.
Two inmates made a similar jailbreak from a St-Jerome, Que. prison in March 2013.
A helicopter pilot was forced at gunpoint to fly to the prison on a Sunday afternoon.
Two inmates at the facility, which is about 60 kilometres from Montreal, climbed a rope ladder into the hovering helicopter and fled.
The two escapees and the two men accused of hijacking the chopper were picked up by police in Mont-Tremblant, about 85 kilometres away, within a few hours of the escape.