A booby-trapped drone has killed two Kurdish Peshmerga fighters and badly wounded two French soldiers battling so-called Islamic State in Iraq.
A Kurdish defence official told Reuters news agency that the drone exploded when the Peshmerga tried to pick it up after it had crashed to the ground.
The incident happened on 2 October, north of the IS-held city of Mosul.
IS militants are said to have tried to use drones to launch attacks at least two other times in the past month.
In response, US-led coalition and Iraqi pro-government forces have been warned to treat any type of small flying aircraft as a potential bomb, according to the New York Times.
But few units have been provided with devices that US troops have to disarm them.
The French newspaper Le Monde reported on Tuesday that the drone involved in the attack 10 days ago had been intercepted in flight and had exploded near the Peshmerga and French soldiers when it crashed to the ground.
A US official told the New York Times the Peshmerga had been examining the drone when a small explosive device disguised as a battery blew up.
It was not clear whether the bomb was detonated remotely or contained a timer.
On Wednesday, the secretary general of the Kurdistan Region's defence ministry, Jabbar al-Yawar, confirmed the death toll and said the French soldiers had been training the Peshmerga at the time of the attack.
The wounded French troops were immediately evacuated to France for medical treatment, Le Monde said, adding that one was "between life and death".
The French government initially declined to comment on the incident, but a spokesman confirmed on Wednesday that French special forces had been injured.
France has sent about 500 troops to Iraq as part of the coalition against IS.
They have been assisting and training troops currently massing around Mosul in preparation for the start of a major offensive to retake the city, which fell to IS in 2014 and is the group's last remaining urban stronghold in Iraq.