A search is underway for a soldier missing at Camp Blanding Joint Training Center in Florida since Wednesday morning.

Cayln McLemor never returned from a land navigation exercise and is thought to be missing somewhere within base boundaries, officials said.

The soldier is a member of the Army Reserve from Alabama who was attending the Basic Leader Course at Camp Blanding’s 211th Regiment Regional Training Institute, according to a statement released by the Florida National Guard on Thursday. The release did not name the soldier, but he was identified in information from the local sheriff’s office.

All permanent-party personnel at Camp Blanding are involved in the search, along with a number of local, state and federal agencies, officials said.

Authorities are concerned that McLemor may have become dehydrated and disoriented during the exercise, which occurred during a time of extreme heat and heavy rain.

Sgt. Keith Smith, public information officer for the Clay County Sheriff’s Office, said search and rescue teams were encountering waist-high to chest-high swamp waters on the navigation course.

“It’s a meticulous and methodical search, but we’re here for the long haul and we’re going to, like I said, just remain positive,” Smith said in a Friday press conference streamed on the sheriff’s office Facebook page.

Smith said rescue teams were able to narrow the search area after recovering some of McLemor’s equipment. Within that area, Smith said wildlife threats are also a point of concern.

“We’re concerned because again, those of us that grew up in this area and have been out here and trained many times, we’ve already encountered water moccasins, wildlife you know that can bite you and grab you out there,” he said in the press conference. “You’ve got a lot of elements out there in that area where ultimately he may have ended up just by getting off the course.”

Smith told reporters there is no reason to believe McLemor went AWOL or is a victim of foul play. The soldier’s family has been notified and is receiving updates during the search.