Prominent Mexican journalist, activist and author Lydia Cacho said death threats she has received in recent days will not paralyze her with fear and stop her from speaking out against injustice.

"They want to silence my work and my defense of women's rights because they know we have them tied down, but they won't succeed," Cacho told Efe after an event in Mexico City with the U.N. high commissioner for human rights, South Africa's Navi Pillay.

Cacho told Efe that she had learned to manage her fears and not let herself be intimidated by the threats.

"Fortunately, we already have signs of where they're coming from and, although we're not very clear of the name of who's responsible, we're close and we'll reveal it," she said.

The threats were sent by e-mail and an anonymous phone call in apparent response to Cacho's latest book, "Las esclavas del poder" (Slaves of Power), in which she denounces global sex-trafficking of women and girls.

The journalist has been the target of threats since 2005, when she published a book, "Los demonios del Eden" (The Demons of Eden), that exposed pedophile rings in Mexico operating under the protection of politicians and business leaders.

For publishing the crimes of Lebanese-born Mexican businessman Jean Succar Kuri and others, Cacho was the victim of kidnapping, psychological torture and police abuses, which she revealed in another book titled "Memorias de una infamia" (Memoirs of an Infamy).

On Wednesday, Cacho and Pillay attended a ceremony to launch a campaign known as "Declarate" (Speak Out), which calls on Mexican society to protect activists and defend human rights.

As part of the campaign, a video distributed through social-networking sites shows how "evil" - in the form of a ghost - spreads fear among people until a group comes together to fight back and vanquish it.

Two Mexican celebrities - rock star Saul Hernandez and award-winning actress Cecilia Suarez - appear on the video and speak of the importance of knowing one's rights and staying united.

The video delivers the message that when a government authority, a business leader or any person commits some type of abuse a victim is left behind who must be defended and has the basic right to defend himself or herself.

Pillay said there is a lack of understanding and acknowledgment of what human rights activists do and that means they often must work under adverse conditions.

During the event, journalist Javier Solorzano said that even though many things are not easy in Mexico "now is not the time to stop and think about difficulties but rather for people to unite and defend themselves."

The event paid tribute to activists such as Marisela Escobedo, who was killed last December for demanding justice for the slaying of her daughter, Rubi Frayre Escobedo; and Catholic priest Alejandro Solalinde, who is frequently threatened for providing protection to migrants.

"People like (Escobedo) shouldn't have died and should not continue to die: I declare," Cacho said in pledging her commitment to protect human rights and support the "Declarate" campaign.

Joining her in expressing their commitment were Pillay, Solorzano, Hernandez, Suarez and all those in attendance at the gathering.

Escobedo was slain while picketing the state government offices in the northern state of Chihuahua to demand justice for her daughter, murdered in August 2008 in Ciudad Juarez, the state's largest city.

At least five community activists have been murdered in the past two years in Chihuahua, where they must contend with violence from drug traffickers and abuses at the hands of federal forces.

More than 3,100 people were slain last year in Juarez, while Chihuahua has accounted for more than a third of the 40,000 drug-war deaths reported nationwide since December 2006.

Solalinde runs the Hermanos en el Camino (Brothers on the Road) shelter in the southern state of Oaxaca, providing assistance to some of the hundreds of thousands of mostly Central American migrants who enter Mexican territory every year with the hope of reaching the United States

The trek is fraught with danger, with criminals and corrupt Mexican officials preying on the migrants.