A man who was thrown out of a bar in Mexico for improper behavior toward women went back and set fire to it, killing 11 people, authorities said Saturday.

The arson attack happened overnight Friday into Saturday in the town of San Luis Rio Colorado, in the northern state of Sonora, which borders the United States.

The fire killed seven men and four women and left four other people hospitalized, the state prosecutor's office in Sonora said.

The attacker was expelled from the bar "for treating women disrespectfully," and then returned and threw a flaming object into it, presumably a Molotov cocktail, the prosecutor's office said.

Authorities are trying to identify the assailant, it added.