A U.S. Army cargo plane crashed in a wooded mountain area of east-central Puerto Rico on a rainy and foggy Wednesday night, killing at least one person, officials said.

Rescuers were unable to reach the crash site more than two hours after the accident because of the dense trees and the dark, said Sandra Virella, a spokeswoman for the State Emergency Management Agency of the U.S. Caribbean territory.

Virella said at least 10 people were believed to have been on the plane, and she said initial information from rescuers indicated at least one of them had died. She had no reports on injuries.

The police air unit and the U.S. Navy said it appeared to be a Hercules C-130 plane, and Navy Lt. Corey Barker said it belonged to the Army Special Forces Command.

A spokesman for the police air unit, Elpidio Marrero, said the C-130 came down near the San Salvador neighborhood of Caguas at about 9:30 p.m. Caguas is about 20 miles south of San Juan, the capital.

In the area of the crash site late Wednesday, a reporter for Univision television reported seeing flares lighting up the sky. Virella said rescuers on the ground were lighting flares to try to direct helicopters to the scene.