The helicopter traveled about 100 yards into U.S. territory during an anti-drug operation, fired two shots at the ground near the presence of U.S. agents on Arizona's Tohono O'odham Indian Nation, which abuts Mexico on the U.S. side of the border, then returned to Mexican airspace.
No one was injured, and the U.S. agents were not injured. Mexican authorities, who did not offer details regarding for whom they were searching, called U.S. authorities and acknowledged the mistake, a U.S. law enforcement official said.
Notable deaths of 2014 [PHOTOS]
Syrian Al Qaida group executes Lebanese soldier