A new video published by the Islamic State in the Iraqi city of Mosul shows the terror group using an attack drone against enemies for the first time. The video, released Monday, appears as an attempt to boost ISIS’ members morale amid reports that the U.S-backed Iraqi forces have managed to retake the eastern half of Mosul after three months of intense battles.

The 45-second video is just a “trailer” from a longer piece set to be released by Nineveh Province, the ISIS branch fighting around Mosul. The video features scenes from the ground battles between ISIS and the local Iraqi forces and suicide operations sent by the Jihadi group against the enemies. The final scene shows an alleged ISIS’ drone dropping two unidentified bombs on a group of troops on the ground.

Previous ISIS propaganda video showed ISIS militants using aerial reconnaissance footage shot from a drone, and live video feeds inside a command room during assaults, but this is the first time the group has shown use of an unmanned aerial vehicle for attack.

The operation to take back Mosul launched in mid-October and is led by Iraqi forces, Kurdish Peshmerga and Iranian-backed Shiite forces on the ground, alongside U.S and other foreign air support. The local Iraqi forces reportedly managed to retake all the eastern half of the city, which is also the most important ISIS’ stronghold in Iraq. More than 100,000 militants are reportedly taking part in the operation, the largest offensive in Iraq since the U.S. invasion of 2003.