The attacks on both Mexican and foreign tourists this week "will not go unpunished," the Guerrero state government said.
Gunmen raped six Spanish tourists on the outskirts of the Pacific resort city of Acapulco around 3:00 a.m. Monday.
The sexual assaults occurred in Playa Bonfil, located in the eastern section of Acapulco, one of Mexico's most popular tourist destinations.
Officials are "in constant contact with the victims and Spanish consular authorities in an effort to offer assistance and guarantee unconditional support," the state government said in a statement.
The victims and several male companions were outside their bungalow when five masked assailants armed with handguns accosted the group.
After gagging the men, the attackers forced the group inside the bungalow and assaulted the six Spanish women, though they spared a Mexican woman who was with them.
"We are working in close coordination with federal and local agencies to find the criminals, both in the Acapulco area, where the Spaniards and a national were attacked, and in the Costa Chica, where armed persons attacked two Mexican tourists," the state government said.
Guerrero Attorney General Martha Elva Garzon said Tuesday that investigators had made "important advances" toward solving the case.
The victims' ordeal lasted for about three hours and the assailants took PCs, cell phones, credit cards and other valuables when they left, Garzon said.
Acapulco, one of Mexico's most famous tourist destinations, has been plagued by drug-related violence in recent years.
The Guerrero state government launched a security operation in 2011 with the support of the federal government to step up security in areas frequented by foreign and domestic tourists.
"Operation Safe Guerrero" was launched on Oct. 6, 2011, in an effort to reduce the soaring crime rate in the state. EFE