Nine people were killed and three injured in two drug-related incidents of violence in Monterrey, the capital of the northern Mexican state of Nuevo Leon, a state Security Council spokesman said.
The first incident occurred around 2.30 am when gunmen riding a vehicle opened fire on the Cafe Iguana in downtown Monterrey, killing four people.
The gunmen fired assault rifles at a group of men standing outside the popular cafe.
Three of the men died in front of the cafe and another between some cars in the parking lot.
Unidentified individuals removed three of the bodies from the crime scene without any interference from the municipal police officers who had responded to the shooting.
Paramedics transported three people wounded in the attack to hospitals in Monterrey.
In another incident, soldiers patrolling the highway to Reynosa, a border city located east of the metropolitan area, were attacked around 3.30 am when they ordered a vehicle to stop.
The vehicle's occupants ignored the order to halt and opened fire on the soldiers, who gave chase.
The SUV crashed and burst into flames, killing the five men aboard.
Nuevo Leon and neighbouring Tamaulipas state have been rocked by a wave of violence unleashed by drug traffickers battling for control of smuggling routes into the US.
More than 1,300 people, including about 80 police officers, have died in the violence in Nuevo Leon in the last 14 months.