Clothes are seen in a tunnel entrance at Pedro Juan Caballero city jail in Paraguay. Dozens of inmates escaped from this prison early morning, mostly members of Brazil's criminal group PCC, "Capital First Command." Picture: Marciano Candia/AP

Asuncion - At least 75 inmates, including members of Brazil's most powerful gang, escaped from a Paraguayan prison on Sunday after digging a tunnel in an operation that prison officials were believed to have been aware, the government said.

The director of the prison in the city of Pedro Juan Caballero, near the Brazilian border, was fired along with six other prison officials, Paraguay's Minister of Justice Cecilia Perez told reporters.

The escaped prisoners included gang members from First Capital Command (PCC), Brazil's most powerful and sophisticated organized crime group, the government said.

"It's an operation that took days and it is impossible that the officials did not realize that they were leaving... obviously this was a paid plan," Perez told local radio station Monumental.

A police van is parked at Pedro Juan Caballero city jail main entrance in Paraguay after dozens of inmates escaped from the prison. Picture: Marciano Candia/AP

The border region near Pedro Juan Caballero is considered a transit point for drug-trafficking and other criminal activity by gangs like Brazil's PCC and Comando Vermelho, or Red Command.

Police mount guard at Pedro Juan Caballero city jail entrance in Paraguay. Picture: Marciano Candia/AP

The government said it alerted Brazil's federal police, but the prisoners are believed to still be in Paraguayan territory.

A police tank guards at Pedro Juan Caballero city jail main entrance in Paraguay. Picture: Marciano Candia/AP

"In that area there are many woods and they know the territory... these are highly dangerous people," Paraguayan Attorney General Sandra Quinonez told Monumental.