The Taliban took credit for killing three troops in a green-on-blue attack Kandahar, Afghanistan, on Monday afternoon, but an U.S. Forces-Afghanistan spokesman fired back at the claims on Twitter, clarifying that the only injuries sustained were non-life threatening.

A defense official, who was not authorized to speak on the record, confirmed that all three wounded troops were Americans.

A member of the Afghan National Civil Order Police fired on a coalition convoy, Col. Sonny Leggett tweeted, without providing details about which coalition country they belonged to.

“The attacker was killed by return fire from Resolute Support forces,” he tweeted.

The incident is under investigation, he added.

The attack came two months after another reported insider attack, which killed two 82nd Airborne Division soldiers in Uruzgan province.

To date, the U.S. has lost 17 service members in Afghanistan this year.