A gang of gunmen killed an off-duty U.S. airman and five other people early Wednesday at a bar in the Mexican border city of Ciudad Juarez, authorities said.
Four other men were killed outside an elementary school in another part of town, raising to 30 the number of homicides in Ciudad Juarez in just four days.
There was no immediate information on a motive for the early morning attack at the Amadeus bar, which also left a seventh person wounded, said Arturo Sandoval, a spokesman for prosecutors in northern Chihuahua state. But the methods bore the hallmarks of attacks by drug cartels.
Staff Sgt. David Booher, assigned to the medical unit of the 49th Fighter Wing at Holloman Air Force outside Alamogordo, N.M., about 90 miles north of Ciudad Juarez, was among those killed in the bar, the U.S. Air Force said.
Earlier this year, the 12th Air Force barred airmen from traveling in Mexico's Chihuahua state. Soldiers from Fort Bliss, just outside El Paso, Texas, across the border from Juarez, also are barred from going to Chihuahua.
One of the highest homicide rates
Prosecutors later said four men were found dead outside the rear perimeter wall of the Pedro E. Medina Gonzalez primary school in another part of the city. Classes were in session at the time.
The wall, which abuts the school's playing fields, was pockmarked by bullets. A sign posted on the government-run school's entrance said classes were suspended for security reasons.
About 1,900 people have died in drug-related killings in Ciudad Juarez so far this year. The city has one of the highest homicide rates in the world.
Elsewhere, the new police chief of San Pedro Garza Garcia, one of Mexico's most affluent cities, vowed to fire corrupt cops. In an interview with El Norte newspaper, Gonzalo Adalid also promised to create incentives for loyalty so police "will not have to ask for a cent from anyone."
Last month, soldiers detained 20 police officers from San Pedro, a suburb of the northern city of Monterrey for allegedly collaborating with the Beltran Levya drug cartel.
President Felipe Calderon has acknowledged that corruption permeates Mexican police at all levels. He has deployed tens of thousands of army soldiers and federal police across the country to lead the battle against cartels.