IRAQI KURDISTAN—Kurdish counterterrorism forces, or Diji Terror, are some of the best trained and equipped in the fight against the Islamic State. They were set up by the U.S. military in 2002 to battle extremists in the mountains of Iraqi Kurdistan.

Today, they battle IS — or ISIL, as it is also known —in broad daylight and in daring nighttime raids.

Lahor Talabani, who leads this force, believes in the importance of knowing your enemy well.

"There's a difference between the locals and the foreign fighters,” he said. “Some of the locals actually picked up weapons and joined ISIL because they had no choice. Their territory was taken over by ISIL by force. Some of them ended up joining ISIL. … The locals are not willing to die. They are in the ranks of ISIL and they give up easily, and we have a lot detainees who are locals. When they know that this is the end, they give up. They don't go all the way."

Understanding the needs and psychology of the local population is one of Talabani's strategies.

Though he's a Kurd, Talabani understands the importance of working with Iraq's Sunni population.

"Side by side of the military actions that we're taking, there needs to be some sort of political process,” he said. “There needs to be some sort of reassurance for the Sunnis, also, that they will be involved in the future of Iraq."

When the Iraqi military launched Operation Conquest on March 24 to retake Mosul, many — including Talabani — said they doubted the army's readiness to retake the city. It's not just about military capacity, he warned, it's also about sectarianism.

"Whatever force is going to take Mosul should be a Sunni-blessed force,” he said. “Don't forget that defeating ISIL cannot only be done by pushing in this front in Mosul. We need to take away this grass-roots support that's already there in Mosul, from the tribal leaders to ISIL.”

The operation to liberate the city of Mosul is expected to take up to a year, but it could take much longer to push the extremists out of the entire country.

Elite forces like Diji Terror, backed by coalition airstrikes, have made significant headway against the militants. But Iraqis themselves know that it will take more than military might to defeat Islamic State.