MEXICO CITY, Mexico (AFP)—The gunman who killed a Canadian tourist and wounded 13 others at Mexico’s famed Teotihuacan pyramids had planned the attack days in advance, officials said Tuesday, as evidence pointed to him being inspired by a US massacre.

President Claudia Sheinbuam called for tighter gun controls at tourist areas after Monday’s attack — which comes just weeks before her country hosts several World Cup football matches.

Mexico State Prosecutor Jose Luis Cervantes, speaking at a press conference alongside Sheinbaum on Tuesday, said the gunman had made multiple visits to the pyramids, “stayed in hotels near the site ahead of time, and from there planned his violent acts.”

The gunman, who shot and killed himself as military personnel moved in, was identified as 27-year-old Mexico City resident Julio Cesar Jasso Ramirez.

The Canadian woman who died was in her early 20s.

Cervantes said that a backpack had been found at the scene with a gun, knife and 52 rounds of ammunition.

The bag contained literature and images linked “to violent events that are known to have occurred in the United States in April 1999,” Cervantes said, in an apparent reference to the infamous Columbine High School shooting.

Two students, aged 17 and 18, attacked the Colorado high school on April 20, 1999, killing 12 classmates and a teacher in a matter of minutes, before taking their own lives.

Several other mass shooters in the United States have subsequently cited the high-profile Columbine tragedy as inspiration for their attacks.

An American who survived Monday’s attack, Jacqueline Gutierrez, told the Mexican newspaper Milenio that the shooter had mentioned Monday being the anniversary of the Columbine massacre.

He also mentioned the pyramid being a place for ritual sacrifices in pre-colonial times, she said.

Designated as a World Heritage site of “outstanding universal value” by the United Nations, the structures at Teotihuacan were built between the first and seventh centuries AD.

The shooting occurred on the Pyramid of the Moon, a 45-meter (nearly 150-foot) high monument that visitors are allowed to climb using steep steps carved of volcanic rock.

Sheinbaum said the shooter had “psychological problems” and “was influenced by events that had occurred abroad.”

She said there were no suspected links to organized crime in the attack, which left at least 13 people injured, including some who suffered gunshot wounds.

Among the wounded, who were taken to different hospitals, were a six-year-old boy and a woman from Colombia, another Canadian woman, a Brazilian man and two Americans.

The president said it was the first time something like this had happened at an archaeological site in Mexico and called for increased security at tourist sites around the country.

“We need to have better security to make sure someone can’t enter an archaeological site, a tourist site, with a firearm,” she said.

According to official tourism figures, Teotihuacan was Mexico’s second most-visited archaeological site last year, trailing only Chichen Itza.

Authorities announced that the site will reopen on Wednesday with increased security protocols.

Juan Carlos Mejia, executive director of the Estur tourism agency, welcomed the announced reinforcement, telling AFP that previously “they never check you” before entering the site, he told AFP.

Mexico City hosts the World Cup’s opening match on June 11.