3 police officers killed in gunbattle in Mexico

Drug cartels are believed to be behind a series of banners hung Monday in this crime-ridden border city that blamed rival gangs for spiraling violence.

The six banners appeared along different avenues of Ciudad Juarez, across from El Paso, Texas, city police spokesman Jaime Torres said. They were taken down immediately.

One of the banners blamed reputed Sinaloa drug-cartel chief Joaquin "Chapo" Guzman for the city's rising crime, including brazen daylight shootouts and increasing numbers of homicides.

"You know that before there wasn't this type of violence," the banner said.

Juarez, located in the northern state of Chihuahua and home base of the powerful Juarez drug cartel, has been among the hardest-hit cities in an explosion of violence across Mexico.

More than a dozen police officers have been killed in the city this year, and several bystanders, including a pregnant woman and a 12-year-old girl, have been killed in the crossfire.

In the neighboring state of Sonora, one state police officer and two federal agents were killed in a running battle with dozens of gunmen that lasted several hours Sunday, Sonora Gov. Eduardo Bours said Monday. One of the gunmen was wounded.

President Felipe Calderon and top police officials say the increasing violence that has plagued numerous states across the country is the cartels' response to a nationwide, organized crime crackdown in which they have sent thousands of police and soldiers to drug hotspots, including Juarez.