The assailants started a fire that ripped through the bar, killing eight women and 15 men, officials said, adding that 13 others injured.
There was no immediate information on the condition of the injured.
The state prosecutor’s office in the Gulf coast state of Veracruz said the search for the attackers was continuing.
The state governor, Cuitláhuac García, suggested a gang dispute was involved. "In Veracruz, criminal gangs are no longer tolerated," García wrote of the attack.
State police identified the establishment as the Bar Caballo Blanco, which is located in a storefront on a busy commercial street in Coatzacoalcos, a Gulf coast city whose main industry has long been oil and oil refining.
ILKHA