NOGALES, Ariz. (AP) -- The U.S. Border Patrol says its agents have been involved in a shooting near the US-Mexico border in the Arizona city of Nogales.
It's not known whether agents were fired upon or whether they fired shots in today's incident.
It's also not known if anyone was injured or what prompted the shooting.
The FBI is investigating.
FBI spokesman Manuel Johnson declined to release details of the investigation, but says the agency's agents are at the scene.