(CNSNews.com) - With 200 more Americans coming over to train and advise them, Iraqi troops are getting ready to move on Mosul, Iraq's second-largest city that was captured by the Islamic State in 2014 to form a key part of its self-declared caliphate.
U.S. military leaders have said all along that the battle to retake Mosul will be very difficult, given the city's size, location, and the enemy's entrenched positions.
But on Monday, President Obama told CBS that the noose is tightening: "My expectation is that by the end of the year, we will have created the conditions whereby Mosul will eventually fall."
Obama said as the Iraqis show more willingness to fight and gain ground, "let's make sure that we're providing them more support.
"We're not doing the fighting ourselves, but when we provide training, when we provide Special Forces who are backing them up, when we are gaining intelligence, working with the coalitions we have, what we've seen is that we can continually tighten the noose."
Speaking at a military school in Paris this past January, Defense Secretary Ash Carter said, "Reaching and retaking Mosul will not be easy, and it will not be quick. There will be many engagements in between. Logistics will become a greater challenge as the Iraqi Security Forces move farther from Baghdad, and the need for operational support from our coalition will likely grow."
At a Feb. 9 hearing of the Senate Armed Services Committee, General Vincent Stewart, the director of the Defense Intelligence Agency, said Mosul will be a "complex operation."
"As you say, it's a large city," Stewart told Sen. Jeff Sessions (R-Ala.). "I'm not as optimistic that we'll be able to turn that in the near-term, in my view, certainly not this year. We may be able to begin the campaign, do some isolation operations around Mosul. But securing or taking Mosul is an extensive operation and not something I see in the next year or so."
At a March 17 hearing, Joint Chiefs Chairman Gen. Joseph Dunford was asked if Mosul will still be controlled by Islamic State fighters by the end of 2016.
"I wouldn't put a timeline on when we would secure Mosul, but again, I would emphasize that operations against Mosul are ongoing," Dunford said. He said re-taking Mosul would be "significantly more difficult" than the American battle to retake Fallujah in 2004-2005, given Mosul's large population and the size of the enemy force.
Dunford said the idea is to "isolate Mosul until the conditions are set for those (ground) forces to be successful in securing" the city.
Deputy Secretary of State Anthony Blinken told CBS's Charlie Rose on Feb. 19 that the Obama administration is "focused" on retaking Mosul, "but we want to do it when we're ready, when the Iraqis are ready, when the time is right. But meanwhile we're squeezing them. We're cutting off the lines of communication. We're making it harder for them to move things back and forth, move between Raqqah and Mosul, move things into Mosul."
Blinken explained that retaking the territory will be particularly difficult, given the "heavily fortified places, urban environments where ISIL or Daesh has put in landmine after landmine, suicide attacks, et cetera. But even once you do that, that's only part one. Then you've got to actually stabilize and hold the communities to rebuild them."
Defense Secretary Carter said earlier this year that if ISIL an be expelled from Raqqa and Mosul, "that will show that there's no such thing as an Islamic State based upon this ideology."