UNDISCLOSED LOCATION, Southwest Asia -- With Islamic State extremists flushed out of their two major strongholds in key tactical victories in Iraq and Syria this year, the fighters remaining in the region continue to fall, according to new estimates from Combined Joint Task Force-Operation Inherent Resolve.

Army Col. Ryan Dillon, a spokesman for the task force, told Military.com in an interview at the unit's headquarters that the official estimate of ISIS' presence had just been revised downward by a significant number.

"Up until today, we had an estimate of less than 3,000," Dillon said Thursday. "But the latest estimate we got today was, there's about 1,000 across Iraq and Syria."

Recent months have seen major tactical victories for the coalition force dedicated to defeating ISIS. In October, the violent sect's self-declared caliphate in Raqqa, Syria, was retaken, with victory declared by the Syrian Democratic Forces on the ground.

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And earlier this month, Iraqi Prime Minister Haider Al-Abadi publicly declared victory over ISIS in Iraq, saying Iraqi forces had control over the Syria-Iraq border and no major ISIS footholds remain in the country.

While task force leaders have made no similar declaration of victory, Dillon said the tempo of some offensive operations is slowing markedly as the ISIS population dwindles.

In November, the task force executed just under 300 airstrikes on ISIS targets in Iraq and Syria, compared with roughly 700 in October and about 1,500 in September, he said.

For the CJTF-OIR, Nov. 26 marked a telling milestone: the first day since the campaign against ISIS began in 2014 that no airstrikes were conducted in either country.

"There have been several days since that we have not conducted airstrikes in Iraq," Dillon added.

There are other indicators that the fight may be winding down.

In late November, the task force announced it was sending home a 400-Marine artillery detachment in Syria, saying combat conditions no longer required it. The unit's replacement had already been identified and trained for what was expected to be a long-term rotational mission.

"With the city liberated and ISIS on the run, the unit has been ordered home," officials said in the announcement. "Its replacements have been called off."

The task force may have similar announcements about downsizing the mission to make in the near future, Dillon said.

At least for now, the task force and the fight aren't going anywhere.

In addition to helping train Iraqi troops and law enforcement to provide for their own security and keep ISIS at bay, the unit is supporting efforts to root out remaining ISIS cells and secure the Iraq-Syria border to prevent the flow of militants, Dillon said.

With the surviving fighters more dispersed, ground troops are focusing on disrupting attempted attacks before they are completed.

A recent frustrated attack in Ramadi, Iraq, this fall illustrated the growing capability of Iraqi Security Forces to defend against ISIS on their own.

The Iraqi troops located vehicle-borne improvised explosive devices on roads and bridges, took actions to neutralize the threat, and then went on the offensive, launching quick-reaction forces that went after the ISIS perpetrators, Dillon said.

"It goes to show a level of capability and capacity and professionalism of the Iraqi security force," he said. "They know what it is like, and they don't want to see it again."

-- Hope Hodge Seck can be reached at hope.seck@military.com. Follow her on Twitter at @HopeSeck.