Mexican authorities said Saturday that at least 19 people died in clashes between armed men and security forces in the gang-plagued northwestern state of Sinaloa, where violence has spiked dramatically following the capture and extradition of convicted drug lord Joaquin "El Chapo" Guzman.
A statement from the State Prosecutor's Office said Friday's violence was touched off by an initial shooting involving "rival groups" of gunmen in the town of Villa Union, about 15 miles (24 kilometers) southeast of the beach resort of Mazatlan. Two people were killed.
"It is presumed that this is the place where the chase began," the statement said.
In a second clash, 15 municipal police officers came under attack on a highway by people riding in pickup trucks.
Marines and state police went to the aid of the local officers, and 17 attackers were killed. Five municipal policemen suffered light wounds, state authorities reported.
Sinaloa is the birthplace of a number of Mexico's drug gang leaders, and killings have risen there after Guzman, the boss of the Sinaloa cartel, was captured and then extradited to the United States earlier this year to face drug charges.
Security experts say a power struggle has since broken out between opposing factions of the cartel, which also faces challenges from other gangs such as the Jalisco New Generation cartel.
During the first five months of the year, homicides jumped by 76 percent in Sinaloa state compared with the same period in 2016, according to government crime statistics.
The killings include the May 15 slaying of Javier Valdez, an award-winning reporter who specialized in covering drug trafficking and organized crime, in the state capital, Culiacan.
Homicides were also up about 30 percent nationwide in Mexico for the January-May period.