Officials of a Mexican political party are apologizing to 650 indigenous people who suffered food poisoning after attending a campaign rally in southern Mexico.

Authorities in the indigenous town of Chilapa had to open an auditorium on Wednesday to treat people who became sick after eating rice tacos and eggs handed out by former mayor Sergio Dolores, who is running for congress.

Guerrero state civil protection officials said adults and children were fainting, throwing up and suffering from diarrhea.