Mexican Helicopter Crosses Into US, Opens Fire Shots from law-enforcement chopper were in vicinity of US Border Patrol agents By John Johnson, Newser Staff Posted Jun 27, 2014 5:35 PM CDT 313 comments Comments File photo of a US Border Patrol agent on the US-Mexico border. (AP Photo/Gregory Bull, File) (Newser) – It looks like Mexico came uncomfortably close to setting off what surely would have been an international mess. A helicopter believed to belong to the Mexican army strayed across the border into Arizona in apparent pursuit of drug smugglers and fired shots in the vicinity of US Border Patrol agents in a marked car, reports Reuters. Nobody was injured, and the chopper returned to Mexico without incident. The Mexican government later acknowledged that the helicopter did indeed cross the border but said it did so accidentally, reports CNN. It's still not clear exactly what happened, but the Arizona Republic notes that another close call occurred in January when a pair of Mexican soldiers in pursuit of drug suspects crossed the border and drew their weapons on Border Patrol agents. The incident ended without shots fired when the US agents explained who they were. Republican Congressman Duncan Hunter of California said last week that Homeland Security knew of 300 incursions into the US by Mexico's police or army since 2004.