US Army Apache helicopters enter Mosul battle, military says

U.S. Army Apache attack helicopters have entered the battle for Mosul in support of Iraqi forces fighting the Islamic State terror group, the head of the famed 101st Airborne Division running the coalition’s ground component told reporters Wednesday.

The helicopters have been “flying at night supporting any nighttime operations that the Iraqi security forces are doing,” Maj. Gen. Gary J. Volesky said from Baghdad.

Also Wednesday, Gen. Joseph Votel, commander of U.S. Central Command, told reporters the Mosul operation was "on track."

The U.S. military assesses ISIS could morph into an insurgent group and carry out “high profile” attacks if it's driven from Mosul, according to Volesky.

“[ISIS] will try to do these high profile spectacular attacks,” he said. “We’ve seen them do that before.”

Volesky said he was concerned any ISIS attacks away from Mosul inside Iraq could stall the operation to liberate the country’s second-largest city.

“One of the things that I'm worried about as well is, you know, the enemy tries a spectacular attack, tries to figure out how to retain some ground in the Euphrates River Valley and causes the attention of the government of Iraq to come back south and that delays or stalls the momentum going forward,” he said.

Echoing earlier statements from senior U.S. officials, Volesky said foreign fighters have remained in Mosul, part of the estimated 3,000-5,000 ISIS fighters in that city. “We expect there will be a fight,” he said.

Volesky said some ISIS leaders have left Mosul, but declined to offer specifics.He said Iraqi forces have liberated 13 villages.

“The Iraqis are ahead of where I thought they would be when this operation started,” he added.

ISIS is launching attacks using mortars and suicide car bombers, Voleskly said, adding that U.S. aircraft were hitting back and in some cases killing ISIS before their fighters could reach the Iraqis.

Volesky said ISIS was using suicide bombers in vehicles to cover the ISIS retreat, which the general said he had not seen ISIS do before, “which really kind of reinforces the point that they are completely on the defensive and are just trying to hold on,” he added.

Volesky said ISIS fighters have been seen retreating into Mosul from the outskirts of town. “They're burning buildings, which we assess to be their headquarters, and a lot of them are moving back into Mosul proper,” he said.

Volesky told reporters there has not been a mass exodus of civilians leaving Mosul. The U.S. military dropped 7 million leaflets from B-52 bombers instructing civilians to stay in their homes.

Iraqi civilians living in villgaes outside Mosul are helping Iraqi forces locate ISIS fighters.

Volesky said that U.S. military troops used to call in airstrikes remained behind the front lines.

In keeping with current policy, the general said the U.S. military would not be supporting any Iranian-backed Shia militia forces in any way. Volesky said the Iranian-backed forces would not be going into Mosul.

Volesky would not comment on reports the Russian military would join the fight to the west of Mosul, where ISIS fighters were in control all the way to Tal Afar, roughly 50 miles away.

“The [U.S.-led] coalition only supports those elements that are under the direct command and control of the Iraqi security forces and the Shia [militas] are not. So we don't support them. And the Iraqis clearly understand that,” Volesky said.

He also said the U.S. military would not take part in any ISIS detainee operations as fighters were captured, leaving that mission up to the Iraqis.

The U.S. military has planned to exploit any intelligence it gets from those fighters or from inside Mosul in the weeks to come, officials said.

Fox News' Kara Rowland and Lucas Tomlinson contributed to this report.