Mexican officials say six people were killed in a series of violent incidents in a town in Guerrero, a southwestern state known for social unrest and drug violence.

State Attorney General Inaki Blanco Cabrera says the violence happened late Friday and early Saturday in Iguala, which is about 200 kilometers (125 miles) south of Mexico City.

He says the first incident involved a clash between police and radical students from a teachers college who had seized buses for a protest. He says police gunfire killed two protesters.

Blanco Cabrera says unidentified armed men later shot at vehicles on the main highway and killed two adults and a minor on a bus.

The sixth victim was found Saturday morning by the army in the same area.