At Mosul Dam, clear evidence of U.S. airstrikes

ERBIL, Iraq -- On Tuesday, Iraq's army launched a new operation to take back more territory from Islamic extremists known as ISIS.

Thanks in large part to U.S. airstrikes, Iraqi troops and Kurdish fighters re-took the Mosul dam Monday. It is a vital source of water and power.

As we made our way towards the dam, the evidence of a hard-fought battle was all around.

Vehicles belonging to ISIS militants had been destroyed, turned into burnt, twisted metal. In some cases it was hard to tell exactly what had been hit.

Kurdish peshmerga soldiers had fought the Sunni militants for five days before the dam was recaptured.

But it was clear on the ground, from the craters and destroyed buildings, that U.S. airstrikes - more than 40 in total - paved the way.

Spent bullet casings and the remnants of burnt tires that ISIS gunmen used as a smokescreen told the story of the firefight on top of the dam.

Gen. Mansour Barzani, the son of Kurdistan's president, said his soldiers killed more than a hundred ISIS militants.

When asked if his forces are capable of holding the dam, he explained that with the support of U.S. airstrikes, it would be much easier to keep control.

But Kurdish peshmerga forces didn't do it alone, and we were reminded of that when a convoy of soldiers from the Iraqi army passed by waving.

Defeating ISIS at the dam was a rare joint operation between Kurdish and Iraqi forces.

Maybe the first of more to come.

Iraqi forces launched a new attack to try to retake Tikrit Tuesday. It has been under ISIS control since early June.