HuffPo reports as "Guatemala Drug War: 200 U.S. Marines Join Anti-Drug Effort":
The Marines are deployed as part of Operation Martillo, a broader effort started last Jan. 15 to stop drug trafficking along the Central American coast. Focused exclusively on drug dealers in airplanes or boats, the U.S.-led operation involves troops or law enforcement agents from Belize, Britain, Canada, Colombia, Costa Rica, El Salvador, France, Guatemala, Honduras, the Netherlands, Nicaragua, Panama and Spain.More at Danger Room:
The Marines’ share of the operation involves chasing drug traffickers with UH-1N Huey helicopters. The Marine contingent has four of the choppers, and the Marines are carrying weapons. “It’s not every day that you have 200-some Marines going to a country in Central and South America aside from conducting training exercises,” Staff Sgt. Earnest Barnes, the public affairs chief for Marine Corps Forces South, tells Danger Room. Prior to the Marines’ deployment, there were only a “handful” of Marines in the country, Barnes says.
However, the Marines can’t technically use their guns except in self-defense, and Barnes wouldn’t say whether they’re authorized to pursue drug traffickers on the ground. The description of what they’re doing, however, suggests that they probably can’t. Instead, they’ll be looking out for suspicious boats — including crude narco-submarines — and then radio the Guatemalans, who do the work seizing their drugs and arresting cartel members. That could be on rivers, or along Guatemala’s two coastlines, reports the Marine Corps Times.