Americans among injured at shooting caught on video at tourist hot spot in Mexico

The gunman, identified by Mexican authorities as Julio César Jasso Ramirez, allegedly visited the pyramids on several occasions to engage "in reconnaissance of the specific locations he intended to utilize for his violent attack," according to officials. 

Among the others injured are six people from the U.S. and others from Russia, Brazil, the Netherlands and Canada, officials said.

"Some people, because they were scared ... threw themselves face-down on the ground, and the rest of us started to go down," the tour guide said.

Officials said the gunman was carrying 52 live rounds of .38 special caliber ammunition inside a plastic bag and a knife.

José Luis Cervantes Martinez, the attorney general of the state of Mexico, said investigators built a "psychopathic profile" of the gunman, which was "characterized by a tendency to copy situations that occurred in other places, at other times and involving other figures."

The Associated Press contributed to this report.