The US military says it targeted a top commander of so-called Islamic State in an air strike in Syria last week.
An initial assessment suggested Tarkhan Batirashvili, also known as Omar Shishani, was likely killed along with 12 other militants, officials said.
The strike took place on Friday near the north-eastern town of Shadaddi, where Shishani had reportedly been sent to bolster local IS forces.
The US had offered a $5m (£3.5m) reward for Shishani, a Georgian national.
The US defence department said his potential removal from the battlefield would negatively impact IS’s ability to recruit foreign fighters and degrade its ability to co-ordinate attacks and defend its strongholds of Raqqa in Syria and Mosul in Iraq.