At least 13 police officers were killed and three others wounded Monday in an ambush by gunmen in the Mexican state of Michoacan, a western region where violence attributed to drug cartels has spiked in recent months, Fox News reports.

The state police officers had gone to a home in the town of El Aguaje in Aguililla municipality to enforce a judicial order when “several armed civilians fired on them,” Michoacan’s state security department said in a statement.

“No attack on the police will go unpunished, and this was a cowardly, devious attack because they laid an ambush in this area of the road,” Gov. Silvano Aureoles said.

Images published in Mexican media showed vehicles burning in the middle of a highway and messages apparently signed by Jalisco New Generation, one of Mexico’s most powerful and rising cartels at the moment. Aureoles said their authenticity was under investigation.

In the afternoon, an Associated Press journalist saw two gutted patrol cars at the entrance to El Aguaje surrounded by hundreds of bullet casings. Two police trucks were towed away.

The streets were nearly devoid of human activity as people apparently decided to stay indoors after the violent events.

After the attack, the area in western Mexico’s so-called “hot lands” was reinforced by federal and state security forces, who set up checkpoints to find the assailants.

Michoacan for decades has been known for marijuana plantations and the making of methamphetamine. It is home to the port of Lázaro Cárdenas, a key entry point for precursor chemicals used to make synthetic drugs.