A longstanding feud over a wind-power project has boiled over into grisly violence, after at least 15 people were bludgeoned to death with stones and cement blocks, and some bodies were partly burned.

The government of the Pacific coast community of San Mateo del Mar in Oaxaca state said that 13 men and two women were killed in what he described as an attack by a group of dissident townspeople on Sunday.

But dissidents who successfully opposed wind power projects in the largely Indigenous area say the mayor’s followers ambushed them at a coronavirus checkpoint and began shooting. The dissidents said “several” people were wounded but did not provide an exact figure on those wounded by gunshots. The prosecutors office in the southern state confirmed the figure of 15 dead, and said a detachment of four detectives, 80 state police and 39 National Guard members had been sent to the scene of the killings.