Prominent Mexican poet and activist Javier Sicilia said Thursday the rights caravan he is heading in southeastern Mexico has not crossed the border into Guatemala by decision of civic groups in the border region.

Sicilia, leader of the Movement for Peace with Justice and Dignity, told MVS radio that the decision was taken by activists on both sides of the frontier, although he said he did not understand the reason behind it.

The bus caravan of some 600 family members of victims of drug-related violence in Mexico headed south from Mexico City last week with the goal of entering Guatemala as a symbolic act of contrition for abuse Central American migrants have suffered at the hand of Mexican criminals and corrupt authorities.

An estimated 300,000 Central Americans undertake the dangerous journey across Mexico each year in a bid to reach the United States. The trek is fraught with danger, with drug-gang members and corrupt Mexican officials preying on the undocumented immigrants.

Members of Sicilia's organization said that for security reasons the Mexican activists did not cross the border and decided to hold the symbolic event on the bridge that links Ciudad Hidalgo, Mexico, with Tecun Uman, Guatemala.

Sicilia said his movement is a "guest" of local activists and will follow "what those groups have decided and organized."

"We're very respectful ... of what organizations in both Guatemala and Central America, as well as those in (the Mexican state of) Chiapas and in Ciudad Hidalgo, have said and agreed to," he said.

Armed, uniformed state and federal agents are accompanying Sicilia's caravan to ensure participants' safety.

The security forces "are honorable people who are doing their job" and monitoring the caravan as it makes its way through "extremely dangerous territory," the poet said, adding that he is not sure if the caravan was not allowed into Guatemala because the agents were armed.

Sicilia had a tense exchange with journalists covering the caravan after one asked him why some news people had left the area and stopped reporting on the trek through southern Mexico.

"The media is here and they're covering whatever they want and are able to," the poet said.

The media should take this opportunity to report on people in this impoverished region of Mexico, because the purpose of the caravan is to make visible "the suffering, the ills of the nation and the thousand pending issues" authorities have with civil society, he said.

The activist had said before the start of the trek that southern Mexico is home to communities that have been excluded by "the modern economic model" and have been "wronged throughout the country's history," especially noting the marginalization of areas with a mostly indigenous population.

Sicilia said Thursday he is not on a political campaign and is only seeking to "contribute something to heal this nation this is falling through our hands."

The poet, who launched his movement after his son was murdered in late March by suspected drug-gang members, met with Mexican President Felipe Calderon in June to express his criticisms of the government's military-based approach to battling the violent drug cartels.

More than 40,000 people have died in drug-related violence in Mexico since Calderon took office and deployed tens of thousands of federal police and army soldiers to drug-war hotspots.

Sicilia is scheduled to meet with the president again a few days after the caravan returns to Mexico City on Sept. 19.

The poet and activist has led numerous marches and demonstrations since his son's murder to demand not only a change in Calderon's drug-war strategy but also an end to impunity for violent crimes.

While several suspects have been arrested in his son's killing, Sicilia says it is shameful that thorough investigations are only seen in high-profile cases.