Forty inmates escaped from jail in the eastern Brazilian city of Recife after a bomb was used to blow a hole in an external wall, authorities there say.
Most of the prisoners were captured after a manhunt through local streets lasting several hours, but two were killed and one remains at large.
It is the second mass breakout in the area in a week.
On Wednesday, 53 men escaped from another jail on the city outskirts and only 13 of them have since been found.
Social media images broadcast on Brazilian TV captured the moment when the explosion ripped through the external wall of the Frei Damiao de Bozanno prison.
Minutes before a man in the street walked up to the prison wall, left a package and moved quickly away.
Seconds after the blast, dozens of men are seen leaping through the hole in a cloud of dust.
They fanned out into the residential streets, many running into houses.
The prison guard’s union said it had warned the authorities that a breakout was imminent.
It said that at the time of the explosion, only half the observation towers at the prison were manned because of staff shortages.
The union said that the state of Pernambuco in which Recife lies has little more than 1,500 prison guards for its penitentiaries when there should be at least 5,000.
Prisons in the state are often run by electing inmates to maintain security alongside the guards.
The union also said that like most Brazilian jails, this one was severely overcrowded.
The prison complex houses four times the number of prisoners it was built for.