The Islamic State continues to be on the offensive in Iraq and Syria, but is increasingly struggling with dissension in the ranks and maintaining control over the towns and villages it has seized,
The New York Times reported.
In recent months, tensions have been mounting within the militant group, in part from new military and financial pressure but also from the difficulty of coordinating a largely decentralized organization.
Specifically, there are reports of dozens of executions and imprisonments of Islamic State fighters who have tried to leave the group, and difficulties with trying to maintain a presence in a battle on numerous fronts. There are also some that are disgruntled about salaries and living conditions.
Meanwhile, some recruits have been turned off after witnessing extreme violence.
"I still feel sick," said Abu Khadija, a Syrian Islamic State defector who told the Times about witnessing the beheadings of 38 Kurdish and Alawite war prisoners in a Syrian town on the Iraqi border.
"I can't eat, I feel I want to throw up, I hate myself," he said. "Honestly, I will never do it. I can kill a man in battle, but I can't cut a human being's head with a knife or a sword."
American officials say that the militant group is still holding its ground and the war is far but won.
The airstrikes have killed more than 8,500 Islamic State members, Gen. Lloyd Austin II, head of United States Central Command, told the House Armed Services Committee last week.
The U.S.-led effort has also been successful in eliminating the group's main source of oil revenue and diminishing the ability of its leaders to command and control troops, the Times said, but officials said the group is increasingly dangerous due to the rise of new affiliates in neighboring countries.
To date, the group has only lost roughly 20 percent of the territory it claimed in Iraq, one defense official told the Times.
"Other than that, we're basically looking at what we had before," Jessica Lewis McFate, research director with the Institute for the Study of War, told the Times. "Their numbers are reduced, but their foreign fighter flows are still robust."
Meanwhile, the U.S. continues to face challenges in countering
the group's propaganda campaign which is generated through social media and drawing roughly 1,000 foreign fighters per month to the cause.
"[ISIS] remains, as we've seen, a formidable and brutal threat," James Clapper Jr., the director of national intelligence, said last week, according to the Times. "We've had some successes taking out a lot of their leadership, but they have replacements."