Gunbattles that broke out in Puerto Peñasco on Thursday evening left at least six people dead, including at least one police officer.

The shootings began around 6 p.m. and turned into a rolling gunfight along one of the beach town's main streets. News reports in the town, known to Americans as Rocky Point, said an atmosphere of hysteria gripped the public after the shooting ended, followed by tension as police and soldiers poured into town.

In a news release, Sonoran state police gave this account of the events:

About 6 p.m. Thursday, police responded to a report of gunfire between two groups at a place called "El Ovalo" near the city's sports complex, and they found three apparent gunmen dead. Officers seized three firearms and a fragmentation grenade at the site, then went looking for suspected participants.

On Fremont Boulevard, the police encountered a Dodge pickup, and a gunman got out of the truck and started firing at them. Police fired back and killed the man, but as the pickup sped off, three people on board began firing, hitting three officers and killing at least one.

In a nearby location, officers found another man shot to death who apparently had participated in the original shootout.

Puerto Peñasco became an important transit point for the Sinaloa Cartel in about 2007, U.S. Drug Enforcement Administration officials said. Occasional shootings have occurred among underworld groups, and the city's police chief was shot and wounded during a traffic stop in 2010.

But until Thursday, the city had largely avoided the public gunfights that have afflicted many cities in Mexico's border region.

Contact reporter Tim Steller at 807-8427 or