Attorney General Jesus Murillo Karam said Wednesday one of the suspects remains at large.
CNN said the six suspects stormed a beach and attacked the tourists, tying up the men and raping the women.
Investigators have not determined whether the suspects are part of a gang, CNN said.
Murillo Karam said one suspect was arrested Tuesday and five others were arrested early Wednesday.
CNN said one of the suspects is just 16 years old.