"What we're starting to see, what they're doing is they're trying to protect the areas they are in control of now, which I might add is some 700 square kilometers less than it was about six months ago," said Pentagon press secretary Rear Adm. John Kirby.
There are official estimates about how much territory ISIL controls, however, he said he could not provide the information because the information was not with him as he spoke to reporters.
ISIL is putting increasing emphasis on protecting "lines of communication," which is the group’s backbone of supply lines and sustainment capability, Kirby said.
"If you look at the airstrikes we're conducting, and you look at some of the operations that are being done by Iraqi and Kurdish forces, you can see that we're trying to disrupt their ability to do that, to preserve those lines of communication," he said.
Earlier this week, Kirby said that ISIL has largely taken "a defensive posture" in Iraq in the last several weeks and that the momentum the group had built up was halted.
The militants still maintain control over Mosul and parts of Anbar province bordering the capital of Baghdad, and Ramadi in particular, he added.
But in Syria, Kirby said there's not as much kinetic activity.
"Kobani still remains threatened, though in control by Kurdish forces, still remains threatened by ISIL. And as you know very well, we continue to conduct airstrikes in and around Kobani as we deem appropriate."
ISIL is trying to defend the area it controls and it is not going on the offense much, he said.
30 ISIL, four Peshmerga killed in clashes
At least 30 ISIL militants and four Iraqi Peshmerga fighters were killed in clashes in northern Iraq Saturday, a Peshmerga source said.
All the casualties took place in Kuwair village located 40 miles (65 kilometers) south of Erbil city.
The ISIL had launched the attack on the village from three fronts, including one from the Zab River using two boats.
The Peshmerga claimed the ISIL dead included four alleged suicide attackers armed with explosives belts. The river boats used by the ISIL were also destroyed, the source said.
Four Peshemrga were also killed and five others were wounded in the clashes, the source added.
This was the first time that the ISIL reportedly used river boats in the attack.