Hundreds of migrants board trains for northern Mexico as they attempt to make their way to the United States, stalked by fear in wake of last week's ranch massacre.
IXTEPEC, OAXACA, MEXICO (AUGUST 31, 2010) REUTERS - In a heavy rain storm, a cargo train pulls into the city of Ixtepec, Oaxaca, carrying hundreds of poor migrants from Central America.
The 300 or so migrants aboard this train have travelled for more than 11 hours from the city of Arriaga in the southern state of Chiapas as stowaways, and once in Oaxaca, their objective is to jump on another locomotive that will carry them north to the U.S. border.
Tens of thousands of Central Americans make this long trek north through Mexico each year on their way to cross the U.S. border illegally as they search for a better life.
They don't just face an arduous journey - they are also risking the wrath of Mexico's violent drug gangs.
The drug gangs are increasingly kidnapping illegal migrants for ransom and forcing them to carry narcotics into the United States as they muscle into the lucrative trade of smuggling people across the border.
The dangers faced by these vulnerable people were highlighted by last week's massacre of 72 migrants at a ranch in northern Mexico, whose blood-spattered bodies were found blindfolded with their hands tied and riddled with bullets.
In a typical scenario, traffickers armed with automatic weapons snatch weary migrants and hold them in cramped houses with little water or food until families pay ransoms of up to $12,000, officials say.
The Mexican army and U.S. border officials say that those who cannot pay are killed, stripped and dumped in shallow graves in remote stretches of the desert frontier.
Thousands are still prepared to make the journey in spite of the risks.
"One takes more risks but has more probabilities to survive. Salaries in my country are low and I can't continue supporting my family any longer," said Guatemalan migrant, Jacobo Coronado.
Jose Alberto Rodriguez, who runs the "Migrantes en el Camino" (Migrants on the road) shelter in Ixtepec, said that when migrants are targetted by gangs, they normally confiscate and destroy their documents so that they cannot be identified.
"The fact is they found them (migrants). Many remain disappeared. The migrant who managed to escape, who was injured, managed to inform authorities. There are many cases where migrants are killed, they are cut into pieces, they throw petrol on their bodies and are set on fire to erase all evidence," he said.
An Honduran migrant, Mario Eduardo Tercero, said a heavy police presence was needed to avoid further deaths.
"More support from the police. I think that if they pinpointed locations (where murders take place) they would prevent more deaths because sometimes they just patrol highways, they stay on the beaten track and it's rare to find a policeman on the road, one tends to find more murderers and rapists."
Despite the worst U.S. recession in decades, poor Latin Americans are still trying to cross illegally into the United States in search of higher wages than at home, walking for days through hot desert or swimming the Rio Grande.
Powerful drug cartels began taking over the trafficking of undocumented migrants into the United States at the start of the decade, seeking to make even bigger profits along their trafficking routes and pushing out small-time smugglers.
As rival gangs wage a lethal war over drug routes into the United States, cartels are kidnapping each others' immigrants or turning on their own clients, using them to smuggle drugs.
The cartels' diversification into migrant trafficking poses another challenge to President Felipe Calderon as he fights a war that has killed more than 28,000 people since he took office in late 2006.