MEXICO CITY (AP) — Six migrants are dead after Mexican soldiers opened fire on a fleeing truck near the border with Guatemala, Mexico's Defense Department said Wednesday.

The department said in a statement that soldiers claimed they heard shots as the trucks and two other vehicles approached their position late Monday in the southern state of Chiapas, near the town of Huixtla.

Two soldiers opened fire on the truck, which was carrying migrants from Egypt, Nepal, Cuba, India, Pakistan and at least one other country. Soldiers then approached the truck and found four of the migrants dead, and 12 wounded.

Two of the wounded later died of their injuries. There was no immediate information on the condition of the other 10. The department did not say whether the migrants died as a result of army fire, or whether any weapons were found in the truck.

There were 17 other migrants in the truck who were unharmed. The vehicle was carrying a total of 33 migrants. The area is common route for smuggling migrants, who are often packed into crowded freight trucks.

The department said the two soldiers who opened fire were relieved of duty pending investigations. In Mexico, any incident involving civilians is subject to civilian prosecution, but soldiers can also face military courts martial for those offenses.

It is not the first time Mexican forces have opened fire on vehicles carrying migrants in the area, which is also the object of turf battles between warring drug cartels.

In the same area in 2021, the quasi-military National Guard opened fire on a pickup truck carrying migrants, killing one and wounding four.

Irineo Mujica, a migrant rights activist who has frequently accompanied caravans of migrants in that area of Chiapas, said he doubted the migrants or their smugglers opened fire.

"It is really impossible that these people would have been shooting at the army," Mujica said. "Most of the time, they get through by paying bribes."

If the deaths were the result of army fire, as appears likely, it could prove a major embarrassment for newly-inaugurated President Claudia Sheinbaum, who took office Tuesday.

Thought the events took place a couple of hours before Sheinbaum formally became president at midnight Monday, she has followed the lead of former president Andrés Manuel López Obrador in giving the armed forces extraordinary powers in law enforcement, state-run companies , airports, trains and construction projects.