A Mexican military helicopter crossed the U.S. border into Arizona and fired on U.S. Border Patrol agents during a drug operation Tuesday before flying back into Mexico, Border Patrol officials said.

Image source: Tohono O'odam official site

Image source: Tohono O’odam Nation

No injuries to agents or damage to U.S. property were reported, a Border Patrol spokesman said, according to KVOA-TV.

The helicopter fired two shots at the agents early Tuesday morning as part of a “drug interdiction operation,” Border Patrol spokesman Andy Adame told KVOA.

“[A] Mexican law enforcement helicopter crossed approximately 100 yards north into Arizona nearly 8 miles southwest of the village of San Miguel on the Tohono O’odham Indian Nation while on a drug interdiction operation near the border,” Adame said in a statement. “Two shots were fired from the helicopter but no injuries or damage to U.S. property were reported. The incident is currently under investigation.”

Mexican officials contacted U.S. authorities soon after and apologized for the incident, Tucson sector Border Patrol union president Art del Cueto told KVOA.

The incident took place on the Tohono O’odham Nation, which resides in southern-central Arizona and parts of northern Mexico.