( CNN ) -- They were young men in their early 20s , all of them joining the armed forces with a desire from an early age to serve their country . They were taken in the battlefield this week , not by enemy combatants but by their comrades in a tragic case of 'friendly fire . ' The U.S. military has not officially released the name of the five American service members who were killed Monday in southern Afghanistan when a coalition jet , called in to help ward off a Taliban attack , mistakenly bombed them . According to NATO , the troops were conducting a security operation . Such operations have been stepped up ahead of Afghanistan 's presidential runoff election , which will take place Saturday . The service members ' unit came under rocket fire from Taliban militants . They called in air support . `` But the airstrike mistakenly bombed their own friends too , '' said Ghulam Sakhi Roghliwanai , the police chief of Zubair province where the incident took place . Their families spoke to CNN affiliates and local newspapers , painting a picture of determined soldiers whose love for their country was rivaled equally by their love for their family . Their deaths bring to 2,328 the number of Americans who have died since the Afghan war began in October 2001 . Here is a snapshot of four of the five service members . CNN is waiting to confirm the identity of the fifth : . Justin Clouse , 22 . Clouse joined the Army a year after graduating high school in Sprague , Washington . He was on his second tour in Afghanistan as a gunner . `` He always wanted to service his country , '' his mother , TIna , told the Spokesman Review newspaper . He had planned to leave the Army next May , marry his fiancee , study engineering and find a job in the oil industry , his mother told the paper . Justin Helton , 24 . Like Clouse , Helton too was engaged to be married . His family told CNN affiliate WBNS that his fiancee moved from Columbus , Ohio , to Fort Bragg in North Carolina to be closer to him . His friends were all looking forward to his return . `` I 've never had a feeling like this , '' friend Tim Hattle told the TV station . `` It just pulled the life right out of me . '' Hattle said he 'll most miss Helton 's easygoing personality . `` He was just an all-around great guy , '' said Hattle . `` Never seen him angry or get upset . Always lifts up people around him . '' Aaron Toppen , 19 . Toppen , of Mokena , Illinois , was a private who had been deployed to Afghanistan in March . `` I 've known the Toppens for years . They 're good people , and Aaron was a good boy , and he was excited about going into the military , '' neighbor Larry Bettenhausen told CNN affiliate WGN . In a Facebook post , his sister , Amanda , called him `` my biggest hero and the bravest man I know . '' Scott Studenmund , 24 . Studenmund knew he wanted to serve his country from a very young age , his family told CNN affiliate KTLA . He had been a Green Beret and an Army staff sergeant , they said . `` He worked his way up the ladder in rank , '' neighbor Marlin James told the station . `` They were so proud of him . We were all very proud of him . '' CNN 's Masoud Popalzai in Kabul contributed to this report .
The five were killed when a coalition jet mistakenly bombed them . Their deaths bring to 2,328 the number of Americans who have died in the Afghan war . Friends and family remember them as brave , loving men .