(Reuters) - Soldiers from Ohio and Illinois are among the five U.S. servicemen killed this week in southern Afghanistan by a "friendly fire" air strike during a security operation, relatives and family friends said on Wednesday.
The men were killed on Monday when their unit, part of the NATO-led International Security Assistance Force, clashed with insurgents and were mistakenly hit by their own forces in an air strike, local police chief Ghulam Sakhi Roghlewanai said.
Justin Helton, 25, a U.S. Army bomb specialist from Beaver, Ohio, was among the dead, his cousin, Mindy Helton, said in a telephone interview.
Aaron Toppen, 19, of Mokena, Illinois, also was killed in the air strike in Afghanistan, said Jennie Swartz, who was acting as a spokeswoman for the Toppen family.
Helton, who had been in the service since 2010, was engaged to be married, Mindy Helton said. Military representatives on Tuesday notified Helton's family of his death, she said.
"We are just exhausted," Helton said. "Yesterday was overwhelming and we are waiting to hear what happens next."
The Pentagon has said investigators were looking into the likelihood that the deaths were caused by friendly fire.
(Reporting by Kim Palmer in Cleveland, Brendan O'Brien in Milwaukee and Hamid Shalizi in Kabul; Writing by David Bailey; Editing by Sandra Maler)