A total of 11 inmates escaped over the weekend from a prison in the central Mexican state of Puebla, officials said.

The inmates slipped out of the prison early Sunday through a hole they made in a wall, the Puebla Public Safety Secretariat said.

The escape occurred at the prison in San Pedro Cholula, a town outside Puebla city, the state capital.

The wall through which the inmates escaped is on one of the town's main avenues in an area full of residences and shops, the secretariat said.

The escaped inmates are all considered extremely dangerous and were doing time for murder.

Four of the 11 inmates belonged to Los Zetas, considered Mexico's most violent drug cartel, Mexican media reported.

Authorities are investigating 17 prison employees, including the warden, to try to determine whether they were involved in the escape.

State police are working with the Federal Police to try to track down the escaped inmates, the secretariat said, adding that checkpoints had been set up in the area.

Mexico's drug cartels sometimes engineer mass prison breaks in response to the killings and arrests of their gunmen.

Heriberto Lazcano Lazcano, known as "El Lazca," deserted from the Mexican army in 1999 and formed Los Zetas with three other soldiers, all members of an elite special operations unit, becoming the armed wing of the Gulf drug cartel.

After several years on the payroll of the Gulf cartel, Los Zetas, considered Mexico's most violent criminal organization, went into the drug business on their own account and now control several lucrative territories.