Four municipal policemen were killed in an ambush by a local organised crime group in Mexico, officials said, without identifying the group.
Michoacan state attorney Marco Vinicio Garibay told AFP that the attackers, who had earlier threatened the officers, staged the morning attack on a road between the cities of Brisenas and Sahuayo, in the western Mexican state.
There is still no sign of the Brisenas police chief, two policemen and another municipal official kidnapped two weeks ago, according to Garibay.
Brisenas is a small town on the border with Jalisco state in central Mexico, where the Knights Templar and the New Generation cartels vie for control of criminal activity, including drug trafficking, kidnapping and extortion.
President Enrique Pena Nieto, who took office on December 1, has vowed to improve public safety in the face of a relentless drug war that has killed more than 60,000 people in the last six years.