MEXICO CITY – The bodies of 12 men killed by hitmen believed linked to drug gangs were found Tuesday in the northern state of Sinaloa, in what appears to be one of the deadliest one-day tolls in violent drug battles in recent years.

The victims – all apparently executed with close-range gunshots – turned up in clumps along an 80-mile stretch of highway between the state capital, Culiacan, and the well-known beach resort of Mazatlan.

“Given the type of weapons used, the type of people (killed) and the objects found at the scene, we are assuming this was a shootout between gangs,” said Sinaloa state Attorney General Luis Antonio Cardenas.

Cardenas was referring to assault rifles and cell phones found alongside some of the victims.

The first group – three men shot to death with assault rifles – were found in a car on a road north of Mazatlan.

A truck driver who was passing by the scene of those killings around midnight was wounded by a stray bullet, Sinaloa’s Attorney General’s Office said in a statement.

Two more men were found shot to death on a roadside near the state capital, Culiacan, early Tuesday. One was identified as Carlos Tirado Lizarraga, alias “El Carlillos,” allegedly a top enforcer for the Sinaloa drug cartel.

Along the same highway later Tuesday, police said they found five more bodies in a Lincoln Navigator truck which had apparently been armor-plated or bulletproofed, and two more bodies just a few yards further down the highway.

All had been shot to death with weapons including AK-47 assault rifles, a favored weapon of drug traffickers.

More assault rifles were found scattered around the truck; they apparently belonged to the dead men, and large numbers of spent shells were found nearby, but it was not immediately clear whether the dead men had fired their weapons in self-defense.

Authorities say that they believe the Sinaloa cartel, led by reputed drug lord Joaquin “El Chapo” Guzman in alliance with Ismael “El Mayo” Zambada, has been waging bloody turf battles against Mexico’s Gulf and Tijuana drug cartels.