MOSUL, Iraq, Oct. 19 (UPI) -- Residents aren't the only ones running away from Mosul, in northern Iraq. Members of the Islamic State terror group, including its leaders, are cutting out quick, too, U.S. military officials said Wednesday.
An alliance of Iraqi, Pershmega and other fighters have been moving toward the contested city since Monday as part of a major effort to rid it from two years of militant control.
"Make no doubt the Iraqi security forces have the momentum," U.S. Army Gen Gary Volesky, commander of Operation Inherent Resolve's ground forces, said Wednesday, adding that coalition forces must continue to apply "unrelenting pressure on the enemy and then the enemy's going to break."
"There are [fewer insurgents] today than there were yesterday; there will be less tomorrow than there are today," he added in a tweet.
Volesky also said the alliance expects the terror group to step up their attacks, including possible chemical attacks, because they're losing.
"I expect that they're going to go into an insurgency mode and they'll try to do these high-profile, spectacular attacks to draw attention away from the losses that they're suffering," he said.
U.S. Army Gen. Joseph L. Votel, U.S. Central Command chief, said Wednesday things near Mosul are going according to plan, or better.
"What I can report to you is that it is on track with the plan," he said. "In some areas, we are right where we expected to be, [and] in other areas we are a little bit ahead of where we expected to be."
Commanders said Tuesday that the march was measured, due to pockets of heavy Islamic State resistance in towns on the way to Mosul. Wednesday's news indicated that momentum is firmly on the side of the U.S.-led alliance.
"We have seen movement out of Mosul; we've got indications that leaders have left," Volesky said.
The U.S. alliance isn't sure yet where the group's leader, Abu Bakr al-Baghdadi, is located. They previously placed him in Mosul but some think he's already fled.
Forces have been approaching from the south, east and northeast -- cutting off potential escape routes for terrorist operatives -- and U.S. air support has made militants' flight even more unlikely.
U.S. officials said advancing forces are also going after oil reserves in the area that is supplying terrorists with operating capital.
Nevertheless, commanders still believe the fight to oust the group from Mosul will be challenging.
"That said, this is an adaptive enemy," Votel said.
Officials believe about 5,000 members of the Islamic State, also called Daesh and ISIL, remain in Mosul.
Thousands of civilians have also left Mosul and crossed into Syria as coalition forces retook nearly all territory south of Iraq's second-largest city away from Islamic State control.
Nearly 1,000 people who left are at a refugee camp in Syria, the United Nations said. Security forces will screen Mosul refugees to determine whether any are masquerading militants.
The terror group is inflicting some damage, though. Commanders have said suicide bombings and other attacks have killed and wounded several coalition fighters. Also, they are believed to be using civilians as human shields to duck approaching troops.
"The situation was miserable there. We all fled due to ISIS," refugee Ahmed Jasim said.
Iraqi News reported Wednesday that security and Peshmerga forces have taken control of more than 80 percent of territory south of Mosul, which includes about 54 villages.