More than 130 inmates escaped Monday from a state prison in northern Mexico, setting off a search by federal police and soldiers in an area close to the U.S. border.

Police have detained the director of the prison in the city of Piedras Negras and two other employees for investigation in the break of 132 prisoners, said Homero Ramos Gloria, Coahuila's State Attorney General.

Police units and Mexican army convoys were deployed outside the city, which sits across the border from Eagle Pass, Texas, to search for the inmates and authorities in Coahuila state offered rewards of up to $15,000 for information leading to the arrests of each prisoner. Visitors were kicked out of the prison but stayed outside waiting for news of relatives.

Ramos said in a press conference that 86 of the inmates were serving sentences or pending trials for federal crimes, such as drug trafficking, and the rest faced state charges. He did not provide details on how the escape occurred.

Other Mexican states have said in the past that they are not prepared to handle highly dangerous federal prisoners.

Coahuila has seen a wave of violence tied to the brutal Zetas cartel's battles with the Sinaloa cartel, allies of the now weakened Gulf Cartel.

Authorities in Coahuila did not say which gang was believed to be behind the prison break.

Last week, Gulf cartel leader Jorge Eduardo Costilla Sanchez was arrested, leading experts to anticipate an increase in violence in parts of northern Mexico as the Zetas Cartel attempted to take over turf.

In December 2010, 153 inmates escaped from a prison in the northern city of Nuevo Laredo, right across Laredo, Texas. Authorities charged 41 guards with aiding the inmates in that escape. Mexico's drug gangs frequently try to break their members out of prison.