TEHRAN, Young Journalists Club (YJC) - Major Adrian Rankine-Galloway, a Pentagon spokesman, said in a statement that the incident took place on Sunday when an improvised explosive device (IED) struck their vehicle, without providing further details.
The statement said the names and nationalities of the casualties would be released once their families were notified.
The Pentagon also claimed that seven American servicemen had been killed in Iraq in the fight against the Daesh Takfiri terrorist group since 2014, including two in the battle to retake the northern city of Mosul.
Reports said a French soldier was also killed while reportedly advising local forces in the fight against Daesh last month, but it is not known if he died in Iraq or Syria.
The US-led coalition of 68 nations has been conducting airstrikes against what are said to be Daesh targets inside Syria since September 2014 without any authorization from the Damascus government or a UN mandate. Such air raids began in Iraq in August of the same year.
The military alliance has repeatedly been accused of targeting and killing civilians. It has also been largely incapable of fulfilling its declared aim of destroying the Takfiri outfit.
Airwars, a UK-based non-profit monitoring group, says at least 5,486 civilians have been killed by coalition air strikes in Iraq and Syria over the past three years.