Arriaga (Mexico) (AFP) - Traveling through Mexico has become even more difficult for Central American migrants like Oscar Vialta and his family, frustrated by tighter immigration rules and a local population reluctant to give them shelter or support as they move toward the United States to try to improve their lives.

Vialta, 42, his wife and two children left Honduras at the beginning of April, joining a migrant caravan heading for the US border.

But when they arrived in Mexico, they ran foul of stiffer new regulations which have restricted them to Mexico's southern states and prevented them from going further north to the border.

Their only legal hope is to be given a humanitarian visa.

"It would let us work and move on," says a frustrated Vialta, "but when we arrived they gave us the runaround and all we got was lies."

He and his family are waiting by the railway tracks in the southern town of Arriaga, planning to hitch a ride on a freight train known as "The Beast". 

Jumping on a freight train is many migrants' means of getting north to the US border, despite the risks of falling off. Some have been mutilated by the wheels as they tried to clamber aboard. 

Another hazard is encountering criminal gangs who prey on vulnerable migrants. Dozens have been kidnapped and murdered by suspected drug gangs who were trying to recruit them.

Since October, tens of thousands of Central Americans and Cubans have traversed Mexico in so-called "caravans" in the hope of obtaining sanctuary in the United States.

Under pressure to do more to curb the mass movement of migrants through its territory, Mexico has tightened a previously open-doors policy.

But that has posed its own problems. On Thursday, at least 1,300 mainly Cuban migrants broke out of a detention center in southern Chiapas state and set fire to the facility in protest at overcrowding.

Around 700 returned soon after to the shelter in Tapachula because they had nowhere else to go, but around 600 are still at large.

US President Donald Trump says the migrants are a threat to US national security and has demanded that Mexico detain them and send them home.

Waiting for that elusive humanitarian visa is not the Vialta family's only problem. They must be prepared to up and run at a moment's notice, wary of swoops by Mexico's National Institute of Migration Police -- the "migras."

The Vialtas has a narrow escape last week when they just managed to evade one such raid, in which more than 300 migrants were rounded up.

"When we saw them, they were almost on top of us, and we managed to get ourselves into a field," he said. Now, he says, they will seek the cover of the woods and fields, away from main roads, to avoid immigration agents.

Jose Vallecillo, 41, lives with the same fear. Traveling with his wife and daughter, he says the attitude of Mexicans towards migrants has changed.

"We've been disappointed. Because the truth is that we are human beings, and migrating is not a crime. You migrate not expecting to do great things but just to make your life a little better," he said.

'No support'

In October of last year, when the first caravans of migrants traveled through Mexico, migrants from Honduras, El Salvador, Guatemala and beyond felt a surge of popular solidarity from Mexicans. Now that seems to have disappeared, in line with a tougher official stance.

"The government of each state put combis, buses, the communities supported us with clothes, shoes, food," said Luis Antonio Lopez, a 42-year-old Nicaraguan migrant who was among thousands to join the first caravans last year. Today, he's still trying to reach the United States.

"Now you don't see that. We don't have the support of either the people or the police," he says as he waits for "The Beast".

Most migrants want to reach the United States because they argue that high levels of violence and poverty are making life impossible in their own countries.