A journalist was shot dead as he left his radio station in southern Mexico on Thursday while a second reporter was murdered in an eastern state, officials said.
Filadelfo Sanchez Sarmiento was heading out following his morning radio show at the La Favorita 103.3 FM station when two men gunned him down in Miahuatlan, southern Oaxaca state, prosecutors said.
Authorities launched an operation to catch the two suspects.
"Mexican authorities must thoroughly investigate this killing and establish a motive -- including any possible connection to journalism -- and bring those responsible to justice," said Carlos Lauria, senior Americas program director of the New York-based Committee to Protect Journalists.
"This crime must not become one of the dozens of unsolved journalist murders in Mexico, which has one of the worst impunity rates in the world," Lauria said.
He was the third journalist to be killed in Oaxaca since April.
Separately, a blogger was murdered in the eastern state of Veracruz, but there were no details about how he died.
The State Commission for the Protection and Attention of Journalists, a government body, said the death of Juan Mendoza Delgado, who was found dead on Wednesday, was declared a "homicide."
Mendoza Delgado was director of a website called "Writing the Truth" and a former crime reporter at a local newspaper.
He is the 13th journalist to be killed in Veracruz since 2010.
Mexico has become one of the most dangerous places in the world for journalists amid a relentless drug war that has killed tens of thousands of people since 2006.
More than 80 media workers have been killed and another 17 reported missing in the past decade, according to Reporters Without Borders.