An American servicemember died in the fighting to retake Mosul from the Islamic State, the Pentagon announced Saturday.

The servicemember died as a result of "wounds sustained in an explosive device blast" outside of Iraq's second-largest city, a Defense Department bulletin said. Mosul is the last remaining stronghold of the Islamic State in northern Iraq, as a U.S.-led coalition of Iraqi government and Kurdish fighters have been working to expel the terrorist organization from the country.

"The city is completely surrounded and ISIS is losing territory every day," Colonel John Dorrian, a spokesman for the counter-Islamic State fight, told reporters on Wednesday.

The Pentagon provided little detail on the circumstances of the servicemember's death, although Dorrian discussed some of the Islamic State's most recent tactics in his press briefing. As the group has lost territory, they have taken to using commercial drones to drop "grenade-size munitions" on coalition forces and civilians.

"They're not game-changers," Dorrian said. "It's not going to stop what's happening on the battlefield, which is them losing, being pushed out of areas, and getting killed. But it does present a tremendous amount of danger to people on the ground when we see these."

The news comes one day after the Defense Department identified two Army Rangers who died fighting the Islamic State in Afghanistan.

"The families and fellow Rangers of Sgt. Joshua 'Josh' Rodgers and Sgt. Cameron Thomas have my respect and sympathies," Defense Secretary Jim Mattis said Friday. "Fighting alongside their Afghan partners, Josh and Cameron proved themselves willing to go into danger and impose a brutal cost on enemies in their path. They carried out their operation against ISIS-K in Afghanistan before making the ultimate sacrifice to defend our nation and our freedoms. Our nation owes them an irredeemable debt, and we give our deepest condolences to their families."