Gunmen opened fire in a bar in northern Mexico, killing 11 people, and the body of a newspaper editor was found shot dead on the side of a highway in two separate attacks, police said Friday.

Police had not uncovered a motive or detained suspects in either shooting.

The body of 40-year-old Miguel Angel Villagomez, owner and editor of La Noticia newspaper in the western state of Michoacan, was found late Thursday near a highway in the neighboring state of Guerrero, police said. He had been shot three times, including once in the head.

Shortly before midnight Thursday, unidentified assailants walked into the Rio Rosas bar in the northern city of Chihuahua and began shooting indiscriminately, said Eduardo Esparza, a spokesman for the prosecutor's office in Chihuahua state.

Chihuahua state has seen hundreds of murders this year as the government attempts to crack down on warring drug cartels. On Aug. 16, gunmen killed 13 people, including a 1-year-old child, at a dance hall in Creel, a picturesque town along a canyon railway popular with tourists.

The Inter-American Press Association said Friday it was outraged by Villagomez's slaying and urged authorities to investigate immediately.

The group noted that since 2006, two journalists have been killed in Michoacan and three have disappeared. Michoacan has suffered heavily from drug turf battles and cartel killings.

In Tijuana, another city plagued by cartel violence, authorities reported on Friday that a total of 91 people have been killed in a wave of gangland homicides since Sept. 26.

Baja California state Attorney General Rommel Moreno called the level of violence "critical and unusual," and said that 11 handwritten messages left next to many of the victims appear to have written by the same person.

The same firearms appear to have been used in about two-thirds of the killings.

Of those cases in which a cause of death has been established, 52 died of gunshots, 19 were strangled, 9 were beaten to death, 6 were suffocated and 5 decapitated.

In one case, authorities said they found human teeth and other remains inside barrels of acid left on a Tijuana street, but investigations continue into that case and those remains were not included in the totals.