Mexico City, Mexico (CNN) -- A group of gunmen ambushed a state police convoy in western Mexico and killed nine officers, state media reported.
Ten officers survived the attack, which occurred in the state of Jalisco on Thursday, state police said, according to the state-run Notimex news agency. One more officer is missing.
The officers were patrolling the southeastern part of the state when gunmen -- armed with assault rifles and grenade launchers -- attacked, the agency said.
After a gunbattle that lasted several hours, the gunmen fled to the neighboring state of Michoacan, Notimex said.
Several deadly attacks have made headlines over the past week in Mexico, where more than 28,000 people have died in drug-related violence since December 2006, when President Felipe Calderon announced a crackdown on cartels.
Earlier Thursday, gunmen shot three trucks carrying factory workers in a border city, killing five and injuring 14 others, Notimex reported, citing local police.
On Wednesday, 15 people were killed at a car wash in the western state of Nayarit.
Gunmen killed 13 people at a drug rehabilitation clinic in the border city of Tijuana on Monday. And at least 14 people were killed in a shooting at a house party where young people had gathered in violence-plagued Ciudad Juarez on Saturday, Notimex said.
The Mexico office of the United Nations High Commission on Human Rights denounced the "succession of high-impact acts."
In a statement released Thursday, the office urged Mexican authorities to intensify efforts to ensure peace, investigate quickly and "capture, prosecute and punish those responsible."