The U.S. is not close to launching a military assault against an Iraqi insurgent group, but "may get to that point" if the militants become a threat to the American homeland, the U.S. military chief said Thursday.

Gen. Martin Dempsey, the chairman of the Joint Chiefs of Staff, told Pentagon reporters that he does not, at this point, believe the U.S. needs to send in an "industrial strength" force with a mountain of supplies to bolster the Iraqi troops as they battle the fast-moving Islamic State in Iraq and Syria insurgency. Instead Dempsey said the most urgent need still is a political solution centred on a more inclusive Iraqi government.

"That's obviously one possibility, but it's not one that personally I think the situation demands," Dempsey said. "I think the situation demands first and foremost that the Iraqi political system find a way to separate the Sunnis who have partnered now with [ISIS], because they have zero confidence in the ability of Iraq's politicians to govern."

SYRIA-CRISIS/IRAQ

ISIS militants in Iraq and Syria have held parades to celebrate the declaration of a caliphate and display the weapons of war they have seized from government forces in both countries. (Reuters)

Offering his most extensive comments to date on the state of Iraq and the U.S. military's effort there, Dempsey said the U.S. is still assessing the situation there, and American troops are not involved in combat.

"This is not 2003. It's not 2006. This is a very different approach than we've taken in the past," Dempsey said.

'We're not there yet'

"Assessing, advising and enabling are very different roads than ... attacking, defeating and disrupting. We may get to that point, if our national interests drive us there, if [ISIS] becomes such a threat to the homeland that the president of the United States, with our advice, decides we have to take direct action. I'm just suggesting to you we're not there yet."

Dempsey laid out a grim assessment of the Iraqi security forces, saying that while they are capable of defending Baghdad, they don't have the logistical ability to launch an offensive. ISIS, meanwhile, has made significant and rapid advances but is now stretched in their ability to control the land it has taken, he said.

Defense Secretary Chuck Hagel, speaking at the same Pentagon news conference, announced that about 200 U.S. military advisers are now in country assessing the situation and they have opened a second joint operating centre in the north in Erbil.

The additional advisers increase the U.S. presence in Iraq by a bit. The U.S. has more than 750 troops in Iraq, mainly providing security for the embassy and the airport, as well as assessing the Iraqi security forces.