The U.S. military headquarters overseeing the ongoing war against the Islamic State group in Iraq and Syria announced Thursday the rough size and timing of a massive spring offensive against the extremist network focusing around the key town of Mosul.

A senior official with U.S. Central Command said Thursday a force of roughly 20,000 to 25,000 Iraqis, retrained by the U.S.-led coalition, will ultimately lay siege to Mosul, likely in April or May. The strategic city is considered the capital of the Sunni provinces of Iraq, much of which came under Islamic State control during their summer offensive from Syria last year.

The military estimates the Islamic State group currently has about 1,000-2,000 fighters in Mosul.

The offensive force will comprise five attack brigades of Iraqi troops, three reserve brigades, three brigades of Kurdish fighters, and a few police brigades and special counterterrorism commandos, the official said, speaking by phone with a group of reporters on the condition of anonymity.

The announcement was an unusual and perhaps unprecedented move. U.S. military spokesman and officials rarely comment on future operations, citing the importance of maintaining secrecy and the security of American and allied troops.



When asked why he chose to reveal these details, the official offered: “Just to describe the level of detail that the Iraqi security forces are doing and the level of commitment that they have to this, and the significance of the upcoming operation.”

“They are absolutely as committed to this,” he added. “There are a lot of pieces that have to come together and we have to make sure the conditions are right. This is their plan. They have bought into it, they are moving forward as if they will execute in the time frame I just described.”

It remains unclear whether the U.S. or any foreign nation will contribute ground forces to the operation. When asked, the official said the coalition has “not closed the door” on the Iraqi request that the U.S. contribute Joint Terminal Attack Controllers, or JTACS – the elite commandos trained in guiding in air strikes to ground targets.

The official provided a fairly optimistic appraisal of combat operations against the Islamic State group, also known as ISIL, ISIS or the derogatory Arabic acronym “Daish.”

“In the degradation that we have applied to ISIL in total, where we thought we would be today, it’s almost double in seven to eight months what they have lost compared to 14 years in Iraq and Afghanistan for U.S. in total,” he said. “There is no organization in the world that can suffer those kinds of casualties and not have a tremendous impact on their ability to achieve their long-term aims.”



Extremists now face an offensive on three fronts, he said: The U.S.-led air campaign, the Iraqi army, and forces loyal to Syrian President Bashar Assad. It remains unclear to what extent the U.S. operates with the Syrian miltiary, operating under a regime President Barack Obama has said is no longer legitimate.

The Islamic State group is now having to make zero-sum decisions on where to deploy its forces, he said, particularly following the devastating air campaign to protect the town of Kobani on the Turkish border from falling into extremist hands.

“He’s in the land of ‘ors’ versus ‘ands’ now,” the official said of the enemy forces.

The official confirmed reports this morning that the U.S. had finalized a deal with Turkey to create one of the training camps for to-be-determined moderate elements of the Syrian opposition ultimately to fight the Islamic State group on their native soil.

He also confirmed reports that Iran has dispatched ground forces to Iraq, though declined to offer any further details.

“We know that there’s an Iranian presence in Iraq,” he said. “It’s largely advisers, to the knowledge that I have.”