MEXICO CITY - Five police officers were killed early Tuesday in a huge Mexico City suburb when they came under attack responding to a call, the city said in a statement.

The officers were killed after arriving in two patrol vehicles around 4 a.m. to the Ecatepec neighbourhood of Ejidos de San Cristobal, the city said. Three died at the scene and two more later while receiving medical attention.

The motive was under investigation. Residents in the city of some 1.6 million people have long complained of out-of-control crime and ineffective police. It's part of Mexico State, which surrounds Mexico City on three sides, where voters will chose a new governor on Sunday.

Meanwhile, gunmen shot and killed a local police chief in the western state of Jalisco on Monday and wounded a woman travelling with him.

The Jalisco state's attorney's office said that the police chief of Huejuquilla El Alto was driving in a Ford Mustang downtown late Monday night when gunmen in multiple vehicles fired on the car. The woman received only a minor wound to her hand.

The statement Tuesday said authorities are investigating the motive. It did not name the victim.

The state is home to one of Mexico's fastest growing drug cartels, the Jalisco New Generation cartel.