Eight journalists were kidnapped in a northern Mexican border city over a period of two weeks in a wave of abductions unprecedented in the Western Hemisphere, the Inter-American Press Association reported.
The group said Wednesday that only three of the journalists kidnapped between Feb. 18 and March 3 in Reynosa, across the border from McAllen, Texas, have reappeared: Two were released alive and one was found dead with signs of torture. Five are still missing.
"The Mexican government must act with urgency and with due force to rescue these journalists alive," said IAPA President Alejandro Aguirre.
Aguirre called the abductions "serious and without precedent in the Western Hemisphere."
The kidnappings are believed to have been carried out by drug gangs in the Gulf coast state of Tamaulipas, where Reynosa is located.
State prosecutors in Tamaulipas and the federal Attorney General's Office in Mexico City could not immediately confirm the report.
The press association said those close to the victims had been too afraid to report the abductions. The reporters work for print, radio and other news media outlets.
On Thursday, the McAllen Monitor, a south Texas newspaper across the border from Reynosa, told its staff that they could not travel to Reynosa on assignment until further notice.
Reynosa and several other cities in Tamaulipas have suffered a wave of shootouts attributed to turf battles between the powerful Gulf drug cartel and its former allies, a gang of hit men known as the Zetas.
The press group cited "IAPA sources who declined to name the victims or file formal complaints with the authorities out of fear of retaliation or further endangering the victims' lives."
The level of intimidation has been such that most Mexican news media did not even report on the Reynosa kidnappings.
The Mexico City newspaper Milenio mentioned one -- but in an opinion column, not a news article.
The column, penned by journalist Ciro Gomez Leyva, said that one of the newspaper's reporters and a cameraman had been briefly abducted in Reynosa and released.
The kidnappers appeared to be cartel hit men, who told the reporters, "Don't come and stir things up on our turf," Gomez Leyva wrote.
The two journalists left Reynosa, deciding that "nothing more should be known or told ... and we obeyed," Gomez Leyva wrote, concluding, "Journalism is dead in Reynosa."
Several international news-media watchdog groups have named Mexico the most dangerous country in the Americas for journalists. Some Mexican media have toned down their coverage of drug-gang violence -- or stopped reporting it altogether -- out of fear for reporters' safety.
Authorities have confirmed the slayings of at least three Mexican journalists so far this year. Twelve reporters were killed in 2009.
All together, 60 journalists have been killed in the country since 2000, according to the Mexican National Human Rights Commission.
AP Writer Christopher Sherman contributed to this report