(CNN) The two Army rangers killed Thursday in Afghanistan might have been struck by friendly fire, Pentagon spokesman Capt. Jeff Davis told reporters on Friday.
He said that "some of the initial indications" point to that as a possibility, but that there is "no indication" of any intentional attacks by Afghanistan soldiers on their American advisers.
Earlier Friday, the Pentagon announced that Sgts. Joshua P. Rodgers, 22, of Bloomington, Illinois, and Cameron H. Thomas, 23, of Kettering, Ohio, were the two soldiers killed Thursday in the Nangarhar Province during an anti-ISIS raid.
There are "no indications it was intentional," Davis said. "War is a very difficult thing, in the heat of battle, in the fog of war the possibility always exists for friendly fire, and that may have been what happened here and that is what we are looking into with this investigation."
The target of the mission was an Islamic State of Iraq and Syria Khurasan (ISIS-K) compound and ISIS emir Abdul Hasib, according to the Pentagon.
Several senior ISIS-K leaders and 35 of the terrorist group's operatives were killed in the raid, according to Davis. The US military suspects Hasib was killed but has not confirmed that, he said.
"We did know going in that this was going to be a very tough fight," Davis noted. "We were going after the leader of ISIS in Afghanistan and doing it in a way that required us to put a large number of people on the ground as part of this mission, and it was a mission that appears to have accomplished its objective ... but it did so at a cost"
Fifty Army rangers and 40 Afghan commandos were dropped by helicopter into Nagarhar Province, within a mile or so of the site where the US dropped the MOAB, or "mother of all bombs," on April 13.
Within minutes, the rangers were surrounded by heavy fire, Davis said, adding that the military called in support from an AC-130 aircraft, F-16s, drones and Apache helicopters.