A shootout among suspected rival drug cartel gunmen left 18 people dead Friday in Mexico, a government official said.  

The gunfight happened in a remote area of northwestern Zacatecas state, said Rocio Aguilar, a spokeswoman for the state government.

The battle was between rival gangs fighting over turf, she told Milenio TV.

On Wednesday the bodies of two police officers were found hanging from a bridge in Zacatecas and since then local media have reported a series of shootouts.

But Aguilera said that so far authorities have not found a link between that grisly find and the big gunbattle in the city of Valparaiso on Friday.

Valparaiso borders Jalisco state, which is a stronghold of a powerful cartel called Jalisco Nueva Generacion. Authorities say it is waging a violent campaign to take control of drug trafficking routes.

Mexico is suffering drug-related violence that has claimed more than 300,000 lives since 2006, when the government started deploying federal army troops to fight the country's drug cartels.