Facing threats, murder and kidnappings, many Mexican journalists have been forced to go into hiding, while the country's vicious drug war has driven some newspapers to self-censorship.

Some journalists have gone into self-imposed exile abroad while others, like Luis Cardona, a 53-year-old who reported in the flashpoint state of Chihuahua, have taken refuge elsewhere in the country.

"I did a story on 15 hostages and I became number 16," said Cardona, who was taken hostage last year while reporting on kidnappings in Chihuahua, which borders the United States.

He told his story to AFP by telephone from an undisclosed location in Mexico, which has become one of the most dangerous countries in the world to be a journalist.

As World Press Freedom Day is commemorated on Friday, Mexico faces a grim record, with Reporters Without Borders saying that 86 media workers have been killed while 18 more have disappeared since 2000.

According to Articulo 19, a Mexican media rights group that helps journalists escape violence, 15 reporters went into hiding within the country last year.

"This is definitely a low estimate, because we don't know the scale of the problem," said Ricardo Gonzalez, director of the organization's journalist protection program.

The internal displacement of journalists casts light on the inadequate security practices of some news organizations as well as the government's failure to guarantee the safety of media workers, Gonzalez said.

Cardona was grabbed by gunmen on September 19, 2012 in the village of Nuevo Casas Grandes in the heart of the "Golden Triangle" region, known for its marijuana and poppy fields and as a route for US-bound drugs.

The journalist had gone there to report on organized crime.

He says his assailants threw him to the ground, beat him and shouted: "Damn journalist! You think you're cool or tough?"

He recalled being beaten with a wooden board, from his heels up to his shoulders, before his kidnappers switched to a whip until he bled. They even took his picture.

Then they put a gun to his head and pulled the trigger, but the firearm was not loaded. After the mock execution, he was dumped on a highway and given the ultimate warning: If you tell the police, you die.

Cardona now tries to stay safe by adhering to the security tips he learned from Articulo 19, which flew him out of Chihuahua after he was released by his kidnappers. He said he was reporting again for a US website, using a fake name.

Journalists are among the victims of a relentless wave of drug violence that has left more than 70,000 people dead and more than 20,000 missing since 2006.

Last week, the mutilated body of a 24-year-old photojournalist was discovered in the Coahuila state capital of Saltillo.

Internet television journalist Gerardo Padilla Blanquet went missing in the same northern city on Tuesday.

Last weekend, around 250 people protested in capital of the eastern state of Veracruz and read the names of nine journalists who have been killed since 2010.

The mutilated bodies of three photographers and another worker from a Veracruz newspaper were discovered on World Press Freedom Day last year, a week after the murder of Regina Martinez, the correspondent of respected national magazine Proceso.

The US-based rights watchdog Freedom House kept Mexico on its list of "Not Free" countries for the press in its latest global report this week.

A Mexican journalist, who asked to use the pseudonym Emilio, said some reporters "are murdered for what they know, not what they write."

Emilio fled Veracruz last year after one of his colleagues was kidnapped and cut to pieces.

After the body parts were found in a black plastic bag, "I got a call on my cellphone from someone saying they were going to kill me," he said, nervously rubbing his hands in a Mexico City cafe.

His news outlet decided to only publish official statements after another colleague was kidnapped and told to stop writing about a cartel.

"Making a living is hard now. Finding a job is difficult," he said. "One colleague is working as a clown at a traffic stoplight and another one is making tacos."