Gunfire broke out on a beach in Mexico’s Caribbean coast resort of Cancun Tuesday, sending tourists scrambling for cover, but authorities said nobody appeared to be injured.

Lucio Hernández Gutiérrez, the chief of police of the coastal state of Quintana Roo, said the attackers apparently pulled up to the beach on jet skis and opened fire at a beach in Cancun’s hotel zone. Hernández Gutiérrez said the jet skis had been found and seized.

One witness to the attack, Rick Lebassa, a tourist from Maine, said two or three gunmen appeared to be shooting into the air with pistols, not at the beach.

“There were two guys and maybe even a third, who came in on jet skis, and what I saw was them shooting up into the sky,” Lebassa said. “I did not see any shots coming in toward the shoreline.”

Lebassa says this was the first incident of this kind he’s seen in his 31 years of coming to Cancun.

“I’m not overly concerned because this is the first time ever,” Lebassa said. “We’ve been coming down for 31 years and we’ve never had any issues.”

Not everyone was as unflappable as Lebassa, though.

Andy Guyrich and Kerry Arms, who were visiting from Minnesota, described more gunshots and terror on the beach.

“We just had to hit the deck,” Guyrich said.

Arms initially thought it was some kind of show.

“There was a delayed reaction for about maybe five seconds, then everybody started scrambling and screaming and crying, and running,” Arms recounted.

The shooting is the latest in a string of violent incidents on the resort-studded coast, and came in the same week that a special battalion of National Guard troops were assigned to protect the area. Mexican marines with bulletproof vests, helmets and assault rifles were seen patrolling Cancun’s tourist-crowded beaches following the Tuesday shooting.

On Nov. 5, a commando of drug gang gunmen stormed a beach at Puerto Morelos, a resort just south of Cancun, and opened fire in front of luxury hotels, executing two drug dealers from a rival gang. The dramatic shooting attack sent tourists scrambling for cover.

State authorities called it “a clash between rival groups of drug dealers on a beach” near two hotels. Several cartels are fighting for the area’s lucrative retail drug trade, including the Jalisco cartel and the a gang allied with the Gulf cartel.

The shootings were the latest chapter in drug gang violence that has sullied the reputation of Mexico’s Caribbean coast as a once-tranquil oasis.

Rival cartels often kill another gang’s street-level dealers in Mexico to eliminate competition and ensure their drugs are sold first. It is not the first time that tourists have been caught in the crossfire of such battles.

The Puerto Morelos shooting came two weeks after a California travel blogger and a German tourist were killed in a similar shootout in the beach town of Tulum in October.

A San Jose, California woman born in India, Anjali Ryot, and German citizen Jennifer Henzold were apparently hit by crossfire from the Oct. 20 drug dealers’ shootout in Tulum, south of Puerto Morelos.

Three other foreign tourists were wounded in the shooting at a street-side eatery that has some outdoor tables, right off Tulum’s main strip. They included two German men and a Dutch woman.

The Tulum gunfight also apparently broke out between two groups that operate street-level drug sales in the area, according to prosecutors.

There have been signs that the situation in Quintana Roo state, where all the resorts are located, was out of control months ago. In June, two men were shot to death on the beach in Tulum and a third was wounded.

And in nearby Playa del Carmen, police stage a massive raid in October on the beach town’s restaurant-lined Quinta Avenida, detaining 26 suspects — most apparently for drug sales — after a city policewoman was shot to death and locked in the trunk of a car last week. Prosecutors said Friday they have arrested a suspect in that killing.

The administration of President Andrés Manuel López Obrador has pinned its hopes on the so-called Maya Riviera, where it has announced plans to build an international airport and a stop for the Maya train, which will run in a loop around the Yucatan peninsula.