MEXICO CITY — Troops shot dead four municipal workers returning from a shooting range in southwestern Mexico on Friday, apparently after mistaking them for criminals, a state official and residents said.

The incident took place in the town of Arcelia and the victims included the director and deputy director of municipal transport as well as two culture department workers, said a Guerrero state interior department official.

Residents said the four were driving back from a shooting club where they practiced and hunted with low-caliber guns.

"There was confusion because one of the four subjects who died was wearing military-style clothes, so the soldiers fired," the official said on condition of anonymity.

The soldiers were taken to the Arcelia prosecutor's office.

Some 200 people blocked the town's main road to protest the shooting. It was the second time that residents block the highway this year to demand that soldiers leave the town.

The military has been deployed across Mexico since 2006 to combat drug cartels. More than 77,000 people have died in drug related violence since then.