A U.S. Air Force helicopter from the 41st Rescue Squadron at Moody Air Force Base in Georgia crashed Sunday in southeastern Afghanistan, killing all six people on board.

The HH-60G Pave Hawk helicopter was on a nighttime medical mercy mission to help two injured Afghan children when it crashed shortly before 9 p.m. about 18 miles north of Ghazni, Afghanistan. The children had suffered head injuries.

"I regret to tell you that all six aboard were confirmed dead," said Master Sgt. Richard Breach, a spokesman at Bagram Air Base, the main U.S. military base in Afghanistan.

Enemy fire did not bring down the helicopter but the cause was under investigation, Breach said. Coalition forces were en route to the crash site.

The remains of the six people on board -- all Air Force members -- have been recovered and were to be flown to Bagram Air Base and prepared for transfer back to the United States, Army spokesman Col. Roger King said.

"You think about the sacrifice these guys made, especially in this case where you've got military personnel who are conducting a flight that's basically a humanitarian mission," King added. "They're trying to go out and save some Afghan kid's life -- it's wrenching."

The weather across Afghanistan was poor at the time and several other flights were grounded.

"The names of those killed are being withheld until their next of kin can be notified," Moody Air Force Base spokeswoman Lt. Alysia Harvey said early Monday.

U.S. military officials in Washington and Afghanistan said the medical evacuation was not connected with Operation Valiant Strike, a mission aimed at rooting out remnants of Al Qaeda and Taliban believed to be operating in the area.

"The Air Force is a close-knit family and the lost of one of own affects us all," Brig. Gen. John Folkerts, commander of the 347th Rescue Wing at Moody, said in a statement. The air force base is located in Valdosta, Ga.

"We wish to express our deepest condolences to the family members of these brave airmen and want them to know that we will not forget the valuable contributions they made to this country and the impact they made on the Air Force," Folkerts said.

The last helicopter crash in Afghanistan was on Jan. 30, when an Army Black Hawk helicopter -- the Army's version of the Pave Hawk -- crashed on a training mission near the Bagram air base, killing four people.

Ten days ago, gunmen fired on a U.S. special forces convoy on the road between the town of Gardez, about 40 miles to the east of the crash, and Khost. The attack led to a firefight involving coalition F-16 and A-10 aircraft and a half-dozen of Apache helicopters. Five of the assailants were killed, and there were no coalition casualties.