U.S. airstrikes and special operations raids killed more than 35 ISIS military commanders in the run up to the Mosul offensive, which is proceeding according to plan, Defense Secretary Ashton Carter said Tuesday.
Carter also joined with French Defense Minister Jean-Yves Le Drian in stressing that the anti-ISIS campaign in Syria will be accelerated to encircle and then retake the self-proclaimed ISIS capital of Raqqa in northeastern Syria, in concert with the Mosul offensive.
Last week, Army Gen. Joseph Votel, commander of U.S. Central Command, made similar remarks on a coordinated campaign against both Mosul and Raqqa. Votel stressed the "simultaneous application of pressure" on Raqqa and Mosul.
In opening remarks at an anti-ISIS coalition meeting in Paris, Carter said that the U.S. had been steadily targeting the Islamic State leadership in and around Mosul, "including many of the highest in the last 90 days. In fact, you might say the most dangerous job in Iraq right now is to be the military emir of Mosul."
The efforts focused on "mid-tier leaders, which our special operations forces and our air forces have done remarkably well. We have caused a lot of confusion in the ranks of the defenders in Mosul by targeting a lot of mid-tier leaders there," Carter said.
The strikes against the leadership "are going to pay off in the coming weeks" in the Mosul offensive as the Iraqi Security Forces press into the city itself, he said.
Carter said he expects to see moves against Raqqa to commence even as the advance on Mosul continues. "We want to see isolation operations begin, oriented at Raqqa, as soon as possible. We're working with our partners there to do that, and so there will be some simultaneity to these two operations. We've long anticipated that."
Army Lt. Gen. Stephen Townsend, overall commander of U.S. and allied efforts in Iraq and Syria as commander of Combined Joint Task Force-Operation Inherent Resolve, was on board with the need to pressure ISIS in both Mosul and Raqqa, Carter said.
"While Mosul may be in the headlines, it's not the only operation underway," Carter said. He noted that Army Gen. Raymond A. "Tony" Thomas III, commander of U.S. Special Operations Command, joined the anti-ISIS coalition meeting in Paris, which also focused on protecting Europe and the U.S. against the ISIS terror threat once Mosul and Raqqa have fallen.
Thomas has been put in charge of preventing ISIS' "external operations," Carter said. "That's another critical issue that we'll discuss today -- our ongoing and intensive efforts to counter ISIL's external operations," he said, using another acronym for the Islamic State of Iraq and Syria.
"We are killing the ISIL terrorists who plot and would carry out such operations, impeding their movement across borders, and hindering their ability to use the Internet to spread ISIL's hateful ideology," he said.
Carter would not rule out that more U.S. and coalition troops might have to be deployed to the region to prevent an ISIS resurgence. He said that more trainers and advisers would be needed to prepare the Iraqis for a continuing counter-insurgency effort against ISIS and to train more Iraqi police and border control personnel.
Both Carter and Le Drian said that the Mosul operation is generally proceeding according to plan. "And while we know it will continue to be a tough fight -- indeed, we'll probably see more resistance as the fight goes on, and almost certainly as our partners approach the core of the city -- I'm confident the Iraqi Security Forces will succeed," Carter said.
On the outskirts of Mosul on Tuesday, Iraq's elite Counter Terrorism Service units advanced to within two miles of the eastern city limits after pushing through the Christian town of Bartella and paused to allow other forces to move into place, Reuters reported.
At the Pentagon on Monday, U.S. military officials said that the advancing force consisted of about 20,000 Iraqi Security Forces and about 15,000 Kurdish Peshmerga fighters. ISIS is estimated to have 3,000 to 5,000 fighters to defend the city where ISIS leader Abu Bakr al-Baghdadi declared the creation of a "caliphate" in June 2014.