Unidentified individuals opened fire on the offices of the El Siglo newspaper in Torreon, a city in the northern Mexican state of Coahuila, for the third day in a row, slightly wounding two people, the daily reported on its Web site Thursday.

The attack on Wednesday caused damage to the offices, the newspaper said.

The unidentified occupants of a vehicle opened fire with AK-47 assault rifles on the building's entrance, hitting the structure 30 times, El Siglo said.

The police officers stationed outside the newspaper offices did not return fire.

Three employees were treated for shock and two others for minor wounds, the newspaper said.

Police and army troops closed off nearby streets, but officials have not reported any arrests.

Five El Siglo employees were kidnapped and held captive for several hours on Feb. 8.

The newspaper refused to disclose details about the kidnapping, but it warned that media members were vulnerable and threatened by crime in Mexico.

The newspaper, which covers the La Laguna region, was the target of several attacks between August 2009 and November 2011.

The La Laguna region, which includes parts of Coahuila and neighboring Durango state, is at the center of a brutal turf war between the Los Zetas and Sinaloa drug cartels, with the Zetas controlling Coahuila's largest cities, including Saltillo, the state capital, Torreon and Piedras Negras. EFE