Eight officers have been killed during a bold ambush on a Mexican prison convoy carrying drug cartel suspects, the authorities say.
Gunmen failed in their bid to free the prisoners - who included senior members of the Beltran Leyva cartel - and escaped in three trucks, say officials.
The brazen attack came as police drove with the nine detainees to a jail in the western state of Nayarit.
Drug violence has killed thousands of people in Mexico in the past few years.
Among the prisoners was alleged Beltran Leyva cartel lieutenant Jeronimo Gamez, known as "The Cousin", who was arrested in January, said the public security department.
Despite Saturday's attack, he and the eight other suspects were delivered to prison in the state capital, Tepic.
"They fulfilled their duty with professionalism, commitment and dedication," the public security department said of the dead officers, reported AP news agency.
The attack came after US President Barack Obama visited Mexico on Thursday and pledged America would step up the fight against Mexican drug cartels.