Two workers at Mexican business daily El Financiero have gone missing in the central state of Zacatecas, the newspaper's deputy general manager said.

"This incident pains all of us who work at El Financiero," Rogelio Cardenas said on Twitter.

He added in another message that the two workers disappeared on the outskirts of the like-named state capital, located 600 kilometers (370 miles) northwest of Mexico City.

Sources with the daily consulted by Efe said state and federal authorities were investigating the case.

Separately, a group of assailants carried out an attack early Tuesday on the offices of Mexican daily El Siglo de Torreon in the northern state of Coahuila, a spokesperson with that media outlet told Efe.

No injuries were reported.

The spokesperson said a trio of assailants set a car ablaze outside the main facade of the newspaper building and then fired shots at the newspaper's sales offices, adding that no arrests have yet been made.

"We don't know the motives yet but we're continuing to work and taking extra precautions while authorities conduct their investigations," the spokesperson said Tuesday by phone.

El Siglo de Torreon also was targeted in an August 2009 attack.

On Oct. 24, the U.N. and Organization of American States envoys for the right to freedom of expression urged the Mexican government to take urgent steps to combat violence against journalists.

According to Mexico's independent National Human Rights Commission, 75 reporters have been killed in the country from 2000 to the present.

That day, the U.N. special rapporteur on freedom of expression, Frank La Rue, said Mexico was the most dangerous country for journalists in the Americas and fifth-deadliest worldwide.

Most of the violence against journalists is thought to come from Mexico's powerful drug cartels and corrupt or abusive public officials.

Conflicts pitting the drug cartels against each other and the security forces have claimed nearly 50,000 lives in Mexico since December 2006.