Six people were dead after gunmen burst into a Tijuana bar popular with university students and opened fire.
The local Public Safety Department said witnesses reported that three people dressed in black rushed into Bar Utopia and started shooting without saying a word.
The state Attorney General's office said two men and a woman died instantly in Friday night's attack. The three others died in hospitals Saturday.
The bar is located in a neighborhood with three university campuses and is popular with students. Most of the victims were under 30 years old.
Police named no suspects or motive.
Drug turf battles have fueled a wave of violence that has swept through Tijuana and other cities across Mexico.