Handicraft vendors and tourists stand outside the Teotihuacan pyramids, which remained closed a day after a gunman opened fire on tourists at the archaeological site on the outskirts of Mexico City, Tuesday. (AP Photo/Marco Ugarte)

MEXICO CITY (AP) — The gunman who opened fire on tourists at Mexico’s iconic Teotihuacan pyramids carried materials that were apparently related to the 1999 shooting at Columbine High School, authorities said Tuesday, a day after the attack that killed a Canadian woman and left at least 13 people injured.

Although officials did not mention Columbine by name, they referred to several books and handwritten notes that belonged to the gunman and referenced attacks in the United States in April 1999. Monday marked the 27th anniversary of the massacre in Colorado.

Among the gunman’s belongings was a photo modified by artificial intelligence showing him alongside the Columbine attackers, according to a state official who spoke to The Associated Press on the condition of anonymity because the official was not authorized to address the media.

Seven people were wounded by gunshots at the archaeological site north of the Mexican capital, the local government said. The nature of the other injuries was not disclosed, but some people fell when the shooting started, including some who were climbing on the pyramids.

The assailant, who acted alone, shot and killed himself, authorities said, and security officials found a gun, a knife and ammunition at the scene.

The attack happened less than two months before Mexico co-hosts the 2026 FIFA World Cup soccer tournament. Mexico’s security secretary, Omar García Harfuch, said major tourist destinations would see a heightened presence of both ground forces and digital “cyber patrols” to prevent threats.

“Yesterday’s attack highlights the urgent need to strengthen our security protocols,” Mexican President Claudia Sheinbaum said. She also noted the importance of analyzing “external influences” that may provoke such violence within the country.

While such attacks are uncommon in Latin America, they are not unheard of. Earlier this month, Argentine authorities linked a teenager to the “true crime community” after the teen killed one student and wounded eight others at a school in the central province of Santa Fe. The community is an online subculture that emerged from forums established after the Columbine massacre to discuss and, in some cases, glorify such violence.

Taken to hospitals after the Mexico attack were six people from the U.S., three from Colombia, one from Russia, one from Brazil, one from the Netherlands and one from Canada, the local government said. The youngest person who was hurt was 6; the oldest was 61, Mexican authorities said.

Authorities identified the attacker as 27-year-old Julio César Jasso Ramírez, a native of Guerrero, Mexico, who, they said, arrived in Teotihuacan a day earlier in an Uber and stayed in a hotel.

Then on Monday shortly before noon, while atop the Pyramid of the Moon, he began firing at tourists with an old revolver while holding a plastic bag containing 52 .38-caliber cartridges in his other hand, said José Luis Cervantes Martínez, the attorney general of the state of Mexico, which includes Teotihuacan.

From the summit of the pyramid, the attacker opened fire on tourists and targeted approaching security forces. Some people threw themselves to the ground and lay motionless to avoid detection. Others fled down the structure as gunshots echoed, Cervantes Martínez said.

National Guard members eventually scaled the pyramid and wounded the attacker in the leg. Witnesses said the gunman shot and killed himself once he felt cornered, according to Cervantes Martínez.