MATAMOROS, Mexico – More than 100 students, teachers and parents found themselves trapped in a primary school amid a shootout between Mexican soldiers and heavily armed gunmen that left two passersby wounded.

Around 80 students, 30 parents and a number of teachers spent 90 minutes on the floor of the Oralia Guerra de Villarreal school in Matamoros, which lies just across the border from Brownsville, Texas.

“We heard shots and we sheltered in three rooms, they were very critical moments,” administrator Rogelio Meza said, adding that the situation was especially difficult because the shooting started just as students were arriving for the school’s second shift.

Second-shift supervisor Reynaldo Treviño Gonzalez said soldiers entered the school and told everyone to stay inside and keep down.

Parents who came to the school to check on their children’s safety were turned away by the troops, whose commanders later declined to offer details about the gunbattle or to say whether any of the gunmen were apprehended.

No one inside the school was hurt, but two pedestrians hit by stray bullets were taken to a nearby hospital.

Violence related to organized crime has claimed more than 15,000 lives in Mexico since December 2006, when newly inaugurated President Felipe Calderon deployed tens of thousands of troops and federal police to battle the country’s powerful drug cartels.

The state of Tamaulipas, which includes Matamoros, is the territory of the Gulf drug cartel. The cartel’s armed wing, Los Zetas, was founded by veterans of an elite unit of the Mexican army. EFE