Coahuila state prosecutors say the attack on the offices of El Siglo de Torreon happened Wednesday afternoon. Just hours earlier, the newspaper published a story detailing an attack on Tuesday in which gunmen wielding automatic rifles fired at least 30 shots at the building's main door from a car.
On Monday, attackers shot at federal police officers guarding the building. No one was injured.
The newspaper's offices have been attacked periodically by gunmen since 2009. No one had been hurt until Wednesday. The newspaper decided after the first attack in 2009 to stop all investigative journalism.