BOYNTON BEACH, Fla. -

Two U.S. soldiers were killed Sunday when their unit was attacked with an improvised explosive device in Afghanistan.

Pfc. Michael J. Metcalf, 22, of Boynton Beach, and First Lt. Jonathan P. Walsh, 28, of Cobb, Ga., died in the attack in the Afghani city of Paktia.

The U.S. Department of Defense said enemy forces attacked their unit with an improvised explosive device.

"I told him, 'Don't leave me because you're the only thing that I have in the world.' So, I know he was fighting to the very end, saying, 'I have to come back to my mother,'" said Metcalf's mother, Kimberly Metcalf. "He hung on, I guess, for a couple hours."

Kimberly Metcalf said she plans to travel to Dover, Del., on Wednesday for the arrival of her son's body. 

"He had a picture of me in his helmet, and he said he carried me every day," Kimberly Metcalf said.

Both men were assigned to the Second Battalion, 504th Infantry, First Brigade Combat Team, 82nd Airborne Division based in Fort Bragg, N.C.

The military said it is still investigating the deaths.