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A large search is underway for two hunters who were last seen in a wilderness area near the border of New Mexico and Colorado. 

Andrew Porter and Ian Stasko, both 25, were elk hunting in the Rio Grande National Forest, the Conejos County Sheriff's Office . Both men were reported overdue to the agency. 

Local newspaper reported that the men had arrived at the area on Sept. 11 and were meant to check in with loved ones the next day. Porter's fiancée called the sheriff's office when the men did not check in, the paper reported.

On Sept. 13, deputies from the sheriff's office went to a trail head in the area to try and locate the men. 

The vehicle that the men had driven to the trail head was found, but deputies did not locate either individual. There was camping gear and backpacks in the vehicle, the sheriff's office said. 

Concerns about recent "heavy rain and bad weather" alarmed the deputies, the sheriff's office said. That spurred the agency to immediately begin search and rescue operations in the area. 

The search was continuing as of Monday, the sheriff's office said in an update to the news release. The New Mexico State Police, as well as local and county resources, are involved. Volunteers from as far as Texas have participated in the search effort, the sheriff's office said. Professional search and rescue personnel and volunteers are working on foot and horseback to comb the area. 

Air assets, including drones and a personally owned Black Hawk helicopter are also participating in the search, the sheriff's office said. 

The Rio Grande National Forest spans more than 1.8 million acres, . It surrounds south-central Colorado's San Luis Valley. The area is popular for hunting, hiking and other outdoor activities.