President Obama's nominee to serve as the Army's top civilian official believes it's "too early to tell" if the United States is winning the fight against Islamic State.

"I think it's too early to tell. We clearly are putting a lot of pressure on ISIS, but they are also showing that they can put pressure on us and they're not contained," Army Secretary nominee Eric Fanning told Senate Armed Services Committee chairman John McCain, R-Ariz., during a Thursday hearing. "I do believe it's a long fight."

Fanning pointed to reports that 6,400 Islamic State fighters have been killed in the last three months and touted the retaking of Ramadi, a major Iraqi city, as signs of recent success, but he couldn't say if Obama's military team has a plan to capture any other major strongholds such as Mosul or Raqqa. "I don't know the specifics of any plan — we're moving in that direction," he said.

Fanning said Congress should pass a bill authorizing the use of military force against the terrorist group, without the restrictions of time or geography that some Democrats desire. He also emphasized the need to reverse the military spending cuts required by sequestration, which is slated to reduce the Army's size to 420,000 service-members.

"Going down to 420 in a sequester environment, I think, would require a whole new set of assumptions and guidance on what the Army is supposed to do and what it's priorities should be," Fanning said.

Fanning demurred when asked if women, who are now allowed entry to combat units following a recent policy change, should be required to register for the draft. "I would say if we are focused on equal opportunity I think a part of that is equal responsibility," he told Iowa Republican Joni Ernst.