Updated

The Department of Homeland Security has taken a lead role in the search for two Afghan men who disappeared while training with the U.S. military at a base in south Georgia, Air Force officials said Friday.

Air Force officials have said that the men were screened before entering the U.S. and that there's no evidence they pose a threat. Homeland Security is coordinating with the U.S. State Department in efforts to locate them, Air Force Lt. Col. Chris Karns said.

The men didn't report Monday to maintenance training with the 81st Fighter Squadron, according to officials at Moody Air Force base near Valdosta.

The two had been at Moody since February as part of training aimed at improving the Afghanistan air force. The military hasn't released their names as part of a policy aimed at protecting them, Karns said.

"Warious terrorist organizations or groups or nefarious groups in their country would seek to inflict harm on them," he said. "They're in the U.S. because it's a safer environment to conduct training and by providing their name and image it potentially introduces unnecessary risk to them and their families."

The program's goal is to train a total of 30 Afghan pilots and 90 Afghan maintenance personnel during a four-year period, Moody Air Force Base said in an August 2014 statement when the program was announced.

It's not the first time foreign servicemen have left training programs at U.S. bases.

On September 20, 2014, three Afghan army officers disappeared from a Massachusetts military base while participating in a training exercise. Two days later, they were detained by Canadian border guards as they tried to enter Canada on the Rainbow Bridge in Niagara Falls, Ontario.

In Lowndes County, which includes areas near the south Georgia base, the sheriff's office has made its school resource officers aware of the search, Lowndes County sheriff's Lt. Stryde Jones said.

"It's just a heightened alert, being more vigilant until they're located," Lowndes County sheriff's Lt. Mike Adams said.