Two people were killed in a shootout between rival gangs on a beach near Cancun, Mexico.
The victims are alleged drug dealers, as the prosecutor announced on Thursday (local time).
Numerous foreign tourists were shocked and frightened by the violence.
"There was a confrontation between members of rival groups of drug traffickers on a beach in Bahía Petempich, Puerto Morelos," the Quintana Roo state attorney general said on Twitter.
Escape in a bathing suit
Tourists on the beach at the Hyatt Ziva Riviera Hotel reported that bathers took cover when the gunfire rang out.
"The guests told me that they were playing volleyball on the beach when the gunman approached and fired shots," wrote US resident Mike Sington on Twitter.
“Everyone ran away from the beach and the pools.
The staff pushed us into hidden rooms behind the kitchens. "
Videos on the online networks showed dozens of tourists - some of them only in bathing suits - taking shelter with the hotel staff in a hotel lobby.
"People hug and cry," said Sington, who claims to be a guest at the Hyatt Ziva Riviera.
Since the government of Mexico City launched a controversial military anti-drug operation in December 2006, more than 300,000 violent deaths have been recorded in the country.
In the past year alone, the authorities recorded more than 36,000 murders.
In October, two foreign tourists were killed in a shootout between suspected drug criminals in Tulum.