Armed men abducted 10 to 12 presumed members of a crime gang who appeared to be celebrating at an upmarket restaurant in the popular Mexican beach resort city of Puerto Vallarta, authorities said.
Jalisco state prosecutor Eduardo Almaguer said at a news conference that preliminary results of the investigation indicated that all involved - kidnappers and kidnapped - were members of criminal organisations.
"They were not tourists or residents who work in legal activities," Almaguer said. "They were people tied to a criminal group we can very clearly presume."
He said authorities believe they know which groups were involved, but declined to name them.
The Jalisco New Generation cartel has become the dominant criminal force in the state. It has battled the powerful Sinaloa cartel for supremacy in other parts of the country, such as Baja California Sur.
Two SUVs carrying five gunmen arrived around 1 am local time at the La Leche restaurant on the city's main boulevard, which runs through the hotel zone between the old beach city and the airport, Almaguer said.
Witnesses reported that four women in the targeted group were not taken by the gunmen, Almaguer said.
He said authorities were looking for those women.
All of those abducted were from the western states of Sinaloa, Nayarit and Jalisco.
Some of those taken away had been on holiday in Puerto Vallarta for a week.
Authorities found lots of drinks and luxury items inside the restaurant, Almaguer said.
Five vehicles were abandoned at the restaurant, among them one with Jalisco license plates, but a false registration, the prosecutor said.
"Obviously, those who acted (the kidnappers) - we presume with the information we have - also belonged to a criminal group that acted against members of another criminal group they located here in Puerto Vallarta," Almaguer said.
Jalisco Governor Aristoteles Sandoval said through his official Twitter account that such violence would not be tolerated and a search was underway for the victims and the kidnappers.
"To the residents and tourists of Puerto Vallarta, I inform you that we have reinforced security so that you can go on as usual," Sandoval wrote.