Mexican authorities say two Central American migrants have died and a dozen more were injured when a truck carrying 41 people overturned in southern Mexico.

The National Institute for Migration says the accident occurred near San Francisco Ixhuatan in Oaxaca state Sunday night. Four of the injured were listed in critical condition, while the others were treated and released.

The migrants from Guatemala and Honduras were packed into a three-ton truck. Authorities say the immigrants paid about $380 each to enter Mexico across the Guatemalan border and travel to the U.S. border. There they were to pay $2,950 more for help entering the U.S.

On June 27, nine immigrants died in a similar accident in the southern state of Tabasco.