Los Angeles (AFP) - A Mexican military helicopter ventured around 100 yards (meters) into US territory and fired two shots, the US border security agency said Friday.
The incident took place Thursday at 5:45 am (1245 GMT) when "a Mexican law enforcement helicopter crossed... north into Arizona," said a statement from US Customs and Border Protection.
"Two shots were fired from the helicopter but no injuries or damage to US property were reported."
The agency said the incident, which occurred some eight miles (13 kilometers) southwest of the village of San Miguel, on the Tohono O'odham Indian Nation, "is currently under investigation."
The Mexican helicopter was on "a law enforcement operation near the border," it added. Local media reported the helicopter was part of a counternarcotics mission.
Earlier this year, a similar incident took place when a Mexican helicopter crossed the border near Sasabe, also in Arizona.