David Jackson

USA TODAY

President Obama struck an aggressive and optimistic tone Monday about U.S.-led efforts to roll back the Islamic State in Iraq and Syria, saying the jihadist group is now on the defensive.

"Along with our coalition partners, we are hammering these terrorists," Obama told troops at Joint Base McGuire-Dix-Lakehurst in New Jersey. "Taking out their fighters, their commanders, hundreds of vehicles and tanks, nearly 200 oil and gas facilities, the infrastructure that funds their terror."

Obama also told the troops: "More than a thousand fighting positions, checkpoints, buildings, barracks — we're taking them out. That's because of the work that you do."

In what seemed like a retort to critics who question the effectiveness of the military operation, Obama said that allied forces have "blunted" the momentum of the Islamic State.

"These terrorists are learning the same thing that the leaders of al-Qaeda have learned the hard way," Obama said. "They may think that they can chalk up some quick victories, but our reach is long. We do not give up."

Obama also warned that the campaign "will take time. But make no mistake, our coalition isn't just going to degrade this barbaric terrorist organization — we're going to destroy it."