CANCUN, Mexico >> Gunfire broke out in a crowded beachfront nightclub throbbing with electronic music early today, causing five deaths and setting off a bloody stampede by screaming concertgoers at an international festival in this Caribbean resort.

At least one person died in the crush to escape and some of the 15 people wounded or injured were hurt in the rush out, authorities said.

Quintana Roo state Attorney General Miguel Angel Pech ruled out any terror attack. He said the shooting erupted when security personnel tried to stop a man from entering the Blue Parrot club with a gun.

Three of those killed were part of the security detail at the 10-day BPM electronic music festival, Pech said. State officials said the dead included two Canadians, an Italian and a Colombian. The gunman apparently fled.

“I was thinking it was the same thing that happened in Paris, some guy just walking in and shooting people at a restaurant, bang bang bang, a terrorist attack,” said New Zealand tourist Tyler Klee, who was outside the club when shots rang out.

“Everyone ran, everyone was terrified, looking for their friends … We were running away and then you hear more shots fired, like you don’t know if you’re going to be shot in the back or not.”

His friend Ben Forbes, from Australia, said: “It happened pretty quickly as well … You still didn’t know where they were, how many there were.”

Peach, the state attorney general, said the 15 people injured included a Mexican woman who was seriously injured.

He said eight of the injured, including two U.S. citizens, were treated for less serious injuries at hospitals and released. Canada’s Global Affairs office confirmed at least one Canadian died and said it was investigating the other reported fatality. It said at least two Canadians were injured. Italy’s Foreign Ministry confirmed one of its citizens died.

Pech said a man apparently tried to enter the nightclub about 2:30 a.m., but was denied access because he had a gun.

The gunman began to exchange fire with another person inside, and festival security personnel who tried to stop the shooting came under fire, he said. He said 20 bullet casings from three different pistols were found at the scene, but it was unclear if the security detail was armed or fired any of the weapons.

Pech said the gunman himself apparently escaped, though three people had been detained nearby. It was not known if they had been involved in the shooting.

“We know of another shooting incident that occurred near the nightclub, but we are investigating whether that is related” to the nightclub shooting, Pech said.

He told local media that authorities were investigating a potential dispute over control of territory by drug dealers or extortion as possible motives.

Quintana Roo Gov. Carlos Joaquin attributed the shooting to “the intolerance and conflict of interests between two people,” but did not specify what those conflicts were. He said the two exchanged gunfire.

The government of the township that includes Playa de Carmen referred in a statement to “attackers who fired shots,” but did not provide further details.

Rodolfo Del Angel, director of police in Quintana Roo, told Milenio TV that the shooting was the result of “a disagreement between people inside” the nightclub and said security guards came under fire when they tried to contain the dispute.

Playa del Carmen has largely been spared the violence that has hit other parts of Mexico.

The state tourism department said the shooting was an “isolated act of violence” and stressed that “the situation in Playa del Carmen is under control and Mexican and foreign tourists can feel protected and safe.”

Without providing nationalities, the state government gave the names of three of those killed. They included Kirk Wilson, who the state identified as the BPM security supervisor at the Blue Parrot, and Daniel Pessina and Rafael Antonio Penaloza Vega.