HIDALGO, Texas (Border Report) — Rounds of gunfire were heard at schools Friday morning from a gun battle south of the border, forcing this border school district to put all of its schools into lockdown, officials said.

Texas Department of Public Safety troopers responded to the incident in which no bullets struck the campuses, but loud gunfire could be heard on the U.S. side, DPS Lt. Chris Olivarez said.

Olivarez said there were no injuries reported on the U.S. side, but migrants are amassing near the McAllen-Hidalgo International Bridge, which leads to Reynosa, Mexico.

“We don’t know the type of weapons or if it was cartel vs. cartel, or cartel vs. military,” Olivarez said.

Staff were present in the school and heard gunfire, Hidalgo Police Chief Romeo Rodriguez told Valley Central.

Rodriguez said as a “precaution” all Hidalgo ISD schools were put on lockdown.

The chief notified Air Marines, U.S. Customs and Border Protection and DPS, he said.

Olivarez says staffers heard “eight rounds of gunfire” coming from south of the Rio Grande, near an area where several migrant camps are located along the Rio Grande.

Olivarez said the gunfire could have come from cartel who control those camps and try to illicit fees from the migrants to smuggle them across the river into the United States.

This is an ongoing story and Border Report will update if more information is received.