Islamic State fighters have used "flying bombs" as they fight to keep control of Mosul, Iraqi special forces have said.
Brigadier General Haider Fadhil said militants deployed two explosives-laden drone aircraft as the battle raged on this week.
Both were destroyed, he said, but gave no further details about the attacks.
It is not the first time IS have used drones in their fight for control in Iraq.
On 2 October, a missile rigged with explosives and controlled by a group linked to IS killed two Peshmerga fighters and badly wounded two French soldiers in the Kurdistan region.
According to Conflict Armament Research, investigators are said to have found evidence of a "drone workshop" in Ramadi, which was retaken from IS in January.
In a report, the UK-based organisation said: "The co-discovery of drone construction and attempts to repurpose missile components plausibly suggests attempts by IS forces to develop some form of weaponised drone."
It is seemingly the latest weapon in the IS arsenal as they continue to resist US-backed Iraqi and Kurdish forces battling to retake their last major stronghold in Iraq.
Two suicide car bombers reportedly made attempts to blow themselves up among troops on Thursday.
In one incident, Iraqi troops fired a rocket to destroy an explosives-laden vehicle after an attempt to detonate it among soldiers positioned in the Gogjali neighbourhood was made.
A second presumed car bomber managed to get away.
The offensive, now in its third week, has seen troops gaining ground against IS.
On Wednesday, coalition planes destroyed a headquarters building, five storage containers, two mortar systems, two fighting positions, a bomb-making factory, a supply cache, a sniper position, an observation post and a culvert.
The strikes also reportedly damaged two tunnels, a bridge and a supply route.
Meanwhile, Colonel John Dorrian, a spokesman for the coalition, has said IS leader Abu Bakr al Baghdadi is losing the ability to control his fighters.
It comes after he urged jihadi followers in Mosul to keep up the fight against Iraqi forces and "make their blood flow as rivers" in an audio message released this week.
Colonel Dorrian said although the military had not officially verified the recording's authenticity, it was "clearly" an effort for IS leaders to communicate with fighters.
"One of the interesting things that we have seen in the English translation of this is that Baghdadi is saying, 'Don't fight amongst yourselves'," he told reporters.
"This is the type of thing that a leader who is losing command and control and ability to keep everybody on the same page says. We don't believe it is going to work."
