At least five people, including four foreigners, have been killed and 15 wounded after a gunman began shooting at a nightclub in Mexico.
The attack happened at the Playa del Carmen resort during the BPM electronic music festival early on Monday.
Quintana Roo State Attorney General Miguel Angel Pech told reporters that two Canadians, an Italian and a Colombian were fatally shot and a woman died in the stampede to get out of the club.
Four people have been arrested on suspicion of being involved in the incident.
The Canadian government confirmed that one of its citizens had died and said it was investigating the reports of a second Canadian death.
Pech said the incident began when a person entered the Blue Parrot nightclub armed about 3am, during the closing of the festival. Another person tried to stop the attacker, sparking a gunfight that drew in security staff.
Fifteen people were injured, including 10 still in hospital. The state government said in a statement that one person was in grave condition.
Pech said two of the dead were BPM security workers but the festival said in a statement that three members of their security team were killed. BPM said the attack was carried out by a lone shooter.
Quintana Roo and the surrounding Yucatan peninsula have traditionally been less violent than other parts of Mexico, with relatively low murder rates.
However, with many foreign tourists and a vibrant night life scene, there has long been an important local drug market in and around Playa Del Carmen.
The organiser of an electronic music event near Playa Del Carmen told Reuters that armed men who claimed to be part of a drug cartel turned up recently at one of his parties, demanding access to sell drugs.
The event's security team decided to let them enter so as to avoid conflict with the men, the organiser said, adding that there were now cells from all the major Mexican cartels operating in Quintana Roo, a wealthy region full of tourists.
The organiser said the situation in Quintana Roo deteriorated after the political party controlling the state government was forced out in local elections last year, a shift that can spark violence as criminal groups struggle to realign their allegiances with the incoming political class.
"They're all fighting for control of the region," said the organizer, who declined to be named for fear of reprisals. "This is an aggression toward any promoter of electronic music in Mexico. It's a wound for the entire community."
He said he thought BPM would have to end, and feared for his own events in the region.
