At least 11 people were killed and seven others wounded in a shootout between army troops and gunmen in the northeastern Mexican state of Tamaulipas, state officials said.

The shootout occurred Wednesday in Reynosa, located across the border from McAllen, Texas, the Tamaulipas Attorney General's Office and the Public Safety Secretariat said in a statement.

The shootout lasted more than an hour and ended close to a Petroleos Mexicanos, or Pemex, facility and in front of a school.

Three dead civilians were found inside a pick-up truck with homemade armor, the AG's office said, adding that the men were armed.

One of the dead men was identified as 30-year-old Javier Antonio Cardenas Lopez, who was from the northwestern state of Sinaloa.

Three men wounded in the shootout - two soldiers and a Pemex employee - were transported to a clinic operated by Pemex, officials said.

One of the wounded soldiers died while being treated by doctors and the other underwent surgery for a gunshot wound in the back and is listed in stable condition.

The Pemex employee was treated for a slight wound and later released.

Five bystanders were wounded and hospitalized, but they are all expected to survive, the AG's office said.

The Gulf, Sinaloa and Los Zetas drug cartels have been fighting for control of Tamaulipas and smuggling routes into the United States.

The war on drugs launched by former President Felipe Calderon, who was in office from 2006 to 2012, left about 70,000 people dead, or an average of 32 per day, in Mexico, officials say.

Calderon, of the conservative National Action Party, or PAN, deployed thousands of soldiers and Federal Police officers across the country to fight drug cartels.

President Enrique Peña Nieto, of the Institutional Revolutionary Party, or PRI, has continued the strategy implemented by Calderon of taking on the cartels, but he has also called for bolstering intelligence capabilities and attacking criminal organizations' entire structures, not just kingpins. EFE