Authorities say four police officers were killed by assailants who opened fired on them during a traffic stop in the central Mexico city of Puebla.

A statement issued Tuesday by the Puebla state public security department says the officers had responded to a report of a suspicious car in a wealthy neighborhood. The officers ordered the car to stop and the occupants shot them with AR-15 rifles.

The department says no one has been arrested and the motive for the attack is unknown.

In the border city of Tijuana, a teenage girl was killed Tuesday by a stray bullet during a shootout between police and gunmen. Tijuana police spokeswoman Cristina Perez says the 15-year-old was waiting for a bus to go to school.