MEXICO CITY- Two reporters among a group of four abducted in northern Mexico last week were freed Saturday by police, a media company said, days after another journalist was released unharmed.

One of the four reporters remains in captivity after the group was kidnapped while covering a protest at a prison in the northern Mexico state of Durango.

In a special broadcast, Milenio Television said their cameraman Jaime Canales and Televisa cameraman Alejandro Hernandez were released Saturday.

The pair disappeared near a prison whose director was accused of allowing inmates out to commit murders for a suspected drug gang.

Hector Gordoa, a reporter with Televisa, was freed Thursday, but a fourth reporter was believed to still be in custody.

The kidnappers had demanded that the news organizations air three videos in which informants alleged ties between the Zetas drug gang and corrupt officials.

Milenio Television complied, airing the videos on its Torreon affiliate.

Battles between the Zetas and the Sinaloa gang are blamed for a wave of violence in the northern states of Durango and Coahuila.

The prison protest broke out Monday after the director and three others were detained over accusations they had allowed inmates out of the prison to commit murders.

Authorities blame some 25,000 murders since 2006 on spiraling drug-related violence, that has continued unabated despite a military crackdown.

The violence has increasingly affected reporters covering the story. At least nine journalists have been killed in Mexico so far this year, according to the Inter-American Commission on Human Rights.