Mexican state of Chiapas.

SAN CRISTOBAL DE LAS CASAS, Mexico — Authorities say two government workers and the police officer escorting them have been killed in a shootout with gunmen who apparently tried to rob money used for a social welfare program in the southern Mexican state of Chiapas.

State spokeswoman for the Social Development Department Adriana Bravo says the head of a federal anti-poverty program, an employee of a government savings bank and the officer were shot dead. Agents are trying to track the armed men down and are investigating if they stole any money.

The attackers ambushed a group of workers and a police unit Monday, surprising them with high-caliber weapons from a hillside as they headed to distribute money to Indian people near the village of Zinacatan, in the highlands of Chiapas, Bravo said. The officers repelled the attack.