The powerful Sinaloa drug cartel and upstart rival Los Zetas were involved in the gun battle than left 29 dead in the western Mexican state of Nayarit, the state Attorney General's Office said Friday.

"First off, we understand it was a clash between gangs linked to the Sinaloa cartel and the so-called Zetas," Nayarit Attorney General Oscar Herrera Lopez told a press conference.

Wednesday's clash, one of the deadliest in recent years in Mexico, took place along Federal Highway 15 on the outskirts of the rural town of Ruiz, which is home to roughly 20,000 people.

The photographs taken at the scene show bodies of people wearing the fatigues, bullet-proof vests, cartridge belts, helmets and boots typical of a military commando.

Authorities found 28 men dead and four others wounded, as well as high-caliber weapons and 14 vehicles - mostly SUVs, two of them armored - at the scene.

One of the wounded men died later at a hospital.

Herrera said all of those slain were from Mexico's Gulf coast, the main bastion of the Zetas, a group founded by deserters from an elite Mexican special forces unit.

Most of the victims were wearing identical uniforms, suggesting that a convoy of Zetas was ambushed by Sinaloa cartel gunmen, the Nayarit AG's office said.

Herrera also said a Guatemalan man died and another "is receiving medical care in the hospital."

Mexican authorities have previously detected Guatemalans - including veterans of the Guatemalan army's Kaibiles commando unit - in the ranks of the Zetas, which have increased their presence in Guatemala in recent years.

Army soldiers confiscated six rifles, a handgun, two hand grenades, 96 ammunition clips, 2,422 rounds of ammunition of different calibers, 14 vehicles of different models, 16 bullet-proof vests, eight cartridge belts, three Kevlar-style helmets, 27 camouflage uniforms, 23 pairs of military boots and other gear.

Approximately 1,000 bullet casings and some undetonated grenades were discovered at the scene.

Authorities in Mexico have come under criticism for the ease with which large convoys of SUVs carrying criminals are able to circulate on the country's highways.

Nayarit is regarded as the territory of the Sinaloa cartel, which is led by Mexico's most-wanted fugitive, Joaquin "El Chapo" (Shorty) Guzman, and is trying to fight off other criminal gangs seeking to infringe on its areas of influence.

That state also is home to a popular tourist zone known as the Riviera Nayarit, which contains dozens of hotels and luxury residences.

Drug-related violence in Mexico has left nearly 40,000 dead since December 2006, when President Felipe Calderon took office and militarized the struggle against the country's heavily armed, well-funded cartels.