Four hundred Guatemalans from among a group of 513 undocumented migrants rescued from two tractor-trailers have been repatriated, Mexican authorities said.

Ten other Guatemalans, four of them minors, will remain in Mexico while authorities verify their immigration status, officials with the INM immigration agency said.

On Tuesday, Mexican police discovered 513 undocumented migrants from several Latin American and Asian countries traveling in subhuman conditions in two tractor-trailers through the southern state of Chiapas, which borders on Guatemala.

Besides the Guatemalans, 32 of the immigrants were from Ecuador, 47 from El Salvador, one each from Honduras and the Dominican Republic, 12 from India, six from Nepal, three from China and a woman who said she is from Japan.

The 400 Guatemalans were returned to their country on board a bus that departed from the Chiapas city of Tapachula.

Meanwhile, the 47 Salvadorans arrived Wednesday night at the immigration station in Tapachula, where they met with El Salvador's consul in Chiapas, Nelson Peña.

The Central American diplomat told Efe that the list of migrants from El Salvador prepared by Mexican authorities will be examined and it will be determined whether any of them are minors.

On Thursday, the consul said, the Salvadorans will be transferred by Mexican authorities to a border crossing point between Guatemala and El Salvador.

The immigrants were being smuggled northwards inside the tractor-trailers, with many of them standing up and supported by ropes. The cargo sections of the vehicles had holes for ventilation.

With regard to the incident, Amnesty International hailed in a communique the intervention of Mexican authorities to rescue the migrants, a situation that "makes clear the vulnerability of tens of thousands of irregular immigrants who pass through Mexico each year."

On Wednesday, Mexican Interior Minister Francisco Blake began a tour of the so-called "migrant route" to inspect the immigration stations in Chiapas, neighboring Oaxaca and in the Gulf coast state of Veracruz.

The complex situation along the Mexico-Guatemala border "is so serious that in Chiapas we have six formal entry points but it is said that there are 56 irregular ones. Therefore, there is the need to strengthen the infrastructure and in that way be able to formally regulate all entries," he said.

Researchers who have studied the issue say traffickers, known as "coyotes," charge Central American immigrants $7,000-$10,000 each to smuggle them through Mexican territory to the United States.

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