Gunmen stormed a restaurant and kidnapped at least 10 people on Monday in the Mexican resort city of Puerto Vallarta.
The heavily armed men arrived in pickup trucks at 0600 GMT and seized their victims from La Leche restaurant.
Prosecutors in the western state of Jalisco said the incident might have come as a result of a war between two rival gangs as the abductees are believed to have ties to the Sinaloa drug cartel.
"There's a very clear suspicion that [the abductees] were members of a criminal group. They weren't tourists or citizens with legal activities," chief prosecutor Eduardo Almaguer told reporters in a press conference.
“They [the kidnappers] were people tied to a criminal group we can very clearly presume,” he said.
Mexican federal authorities including police and troops are searching for the victims.
Almaguer stated that all of those abducted were from the western states of Sinaloa, Nayarit, and Jalisco.
He also said the authorities believe they know which gangs were involved in the incident, but declined to name them.
Puerto Vallarta is home to the Jalisco New Generation drug cartel (CJNG), one of the fastest expanding drug-trafficking criminal groups in Mexico.
CJNG splintered off from the Sinaloa cartel in 2010, after the death of Ignacio “Nacho” Coronel, a local boss of the group.
It has become one of the most powerful drug gangs in the country in recent months by defying law enforcement authorities with a series of guerrilla-like attacks.
Some experts link the group's success to its past strategy of portraying itself as a defender of Mexico against other cartels.
In the past, it has battled the Sinaloa for supremacy in other parts of Mexico, such as Baja California Sur.
Drug wars in Mexico have left more than 100,000 people dead or missing over the last decade.