About 100 soldiers, marines and police located a drug gang safe house in the state capital of Xalapa and surrounded it late Thursday, said Veracruz state Public Safety Secretary Sergio Lopez Esquer.
The gunmen resisted fiercely and a standoff ensued, with authorities firing tear gas into the house and exchanging fire with those inside.
Other gunmen shot up homes and cars in surrounding neighborhoods, apparently to try to draw soldiers away from the safe house.
Security forces finally stormed the house early Friday and seized grenades, ammunition and vehicles, army Gen. Rene Aguilar Paez said. There were no arrests.
The soldiers were responding to tips about armed men traveling in convoys of sport utility vehicles in the area a hallmark of Mexico's drug gangs. There was no immediate information on which cartel is suspected to have been involved.
Officials reported this week that 34,612 people have died in drug-related killings across Mexico in the four years since President Felipe Calderon declared an offensive against drug cartels.
The killings reached their highest level in 2010, jumping by almost 60 percent to 15,273 deaths from 9,616 the previous year.
Also Friday, authorities in the Pacific coast resort of Acapulco reported the discovery of a local prison guard's mutilated body in a parked car.
The guard's face and scalp had been skinned and stretched over the headrest of the front seat. The rest of the body was found in bags in the car, according to a report by police in Guerrero state, where Acapulco is located.
Handwritten messages found in the vehicle were signed by an unknown group calling itself "the baddest cartel" and threatened to do the same to any guard "who messes with the prisoners' families."
In the nearby town of Tecpan, meanwhile, authorities reported a local policemen was found shot to death and hung from a tree.
A message was also found near his body; such notes are frequently left by drug cartels to threaten rivals and authorities.
And in the northern state of Coahuila, prosecutors said Friday that police recovered a car stolen from a local mayor when he was kidnapped and slain earlier this month.
The man driving the car tried to escape from police and opened fire on them with an AK-47 assault rifle, a weapon favored by the cartels. The suspect died when police returned fire, according to a statement from prosecutors.
Three mayors have been killed in Mexico so far this month, and more than a dozen were gunned down in 2010.
The motives in many of the attacks remain unclear.