Gone for more than 24 hours as temperatures drop to near freezing, a missing 3-year-old is the "number one priority" of police in North Carolina, officials said Wednesday.
Casey Lynn Hathaway was last seen playing with relatives outside of his grandmother's house on Tuesday, according to CNN affiliate WTVD . He didn't come inside when the others did.
The FBI, NCIS and dozens of volunteers have joined the effort to find the boy -- described by authorities as 25 pounds and 2 feet 4 inches tall -- as extremely cold temperatures creep in.
"Casey is a small child," Craven County Sheriff Chip Hughes said at a Wednesday news conference. "He's cold, he's hungry."
Hughes said authorities are treating Casey's disappearance as a missing child case but ask the community to report anything "remotely suspicious."
Temperatures are expected to fall to near freezing Thursday in the area near where Casey disappeared, Hughes said, creating concern for authorities, who already are facing rugged, difficult terrain.
Casey's family searched for 45 minutes before calling 911 Tuesday, Hughes said, and since then 10 to 12 other counties and 20 to 25 other sheriffs have joined the search, as have the FBI, NCIS and State Highway Patrol.
The US Marine Corps also has also joined the search effort, Hughes said.
Authorities have employed helicopters, drones and K-9 units, Craven County Emergency Management Director Stanley Kite said Wednesday. Divers also are assessing nearby ponds, WTVD reported.
"Today, hundreds of professional searchers and volunteers walked through rough terrain around the home to try and locate Casey," the Craven County Sheriff's Office said Wednesday. "Volunteers were sent home for the night due to safety concerns. Professionally trained searchers will continue to work overnight. Additional search assets will return in the morning."
The sheriff's office has asked residents to check their properties for signs of the missing boy.
"It's heartbreaking. I have two children so I can only imagine what the family is going through and we're a small community so you don't really expect anything bad to happen here," Jonathan Ipock, youth pastor of New Haven Church, told WTVD.