BEIRUT • The Islamic State in Iraq and Syria's (ISIS) "caliphate" has shrunk to less than 1 per cent of its original size, the US-led coalition has said, as a final onslaught in eastern Syria loomed.
Kurdish-led forces spearheading the offensive have paused operations, but United States President Donald Trump predicted on Wednesday that a final declaration of victory would come next week.
At its height, the hardline proto-state proclaimed by ISIS in June 2014 straddled swathes of land in Syria and Iraq and was roughly the size of Britain.
Major-General Christopher Ghika, the coalition's deputy commander, on Thursday described the size of the last ISIS pocket as "now less than 1 per cent of the original caliphate".
The coalition has been training and providing aerial support to the Syrian Democratic Forces (SDF), which launched an offensive on the last patch of militant territory last September. Two months later, they took Hajin, which was the last town of note under ISIS control and left the militants fighting over a scattering of hamlets in the Euphrates River Valley.
Thousands of suspected ISIS fighters have attempted to blend in with civilians fleeing the militant group's battered last bastion, including a large number of foreigners.
"They are attempting to escape through intermixing with the innocent women and children attempting to flee the fighting," Maj-Gen Ghika said in a statement.
The SDF has set up screening centres to process the droves of haggard people streaming out of ISIS-held territory, often famished and covered in dust. US, French, British and other forces are also actively looking for wanted ISIS operatives among those fleeing the combat zone with civilians.
After weeks of advancing steadily, the SDF halted its ground assault on ISIS' tiny remaining enclave last week, saying the militants were increasingly using civilians as human shields.
The Kurds, who have de facto semi-autonomy in north-eastern Syria, are also engaged in behind-the-scenes diplomatic talks over the fate of the region.
Mr Trump said last December that he had ordered a complete troop withdrawal from Syria, a shock announcement that left the Kurds scrambling for new allies.
Speaking at the State Department on Wednesday, Mr Trump said that US-led troops and their Kurdish allies should formally announce the end of the "caliphate" some time next week.
"Remnants - that's all they have, remnants - but remnants can be very dangerous," Mr Trump said. "Rest assured, we'll do what it takes to defeat every ounce and every last person within the ISIS madness."
The Wall Street Journal reported the complete US pullout will happen by the end of April.
Unless the Trump administration alters course, the military plans to pull a significant portion of its 2,000 troops out by the middle of next month, with a full withdrawal coming by the end of April, the newspaper said on Wednesday. The Pentagon declined to comment on the plans.
While ISIS will soon no longer have fixed positions anywhere in Iraq or Syria, its surviving fighters have reverted to guerilla warfare and remain a potent force.
The militants maintain sleeper cells, including along the border with Iraq and in cities they once ruled, and have carried out periodic hit-and-run attacks.
The SDF arrested 63 suspected militants in the Syrian city of Raqqa on Thursday during an operation against militant sleeper cells, it said in a statement.
At least 48 suspected ISIS members were among them, according to the Britain-based Syrian Observatory for Human Rights.
The Observatory said suspected ISIS sleeper cells have allegedly assassinated at least 50 civilians and 135 SDF fighters in Kurdish-held territory since August.
More than 37,000 people, mostly wives and children of hardline fighters, have fled ISIS territory since the SDF, backed by the US-led coalition, intensified its offensive last December, according to the Observatory, which said that figure includes some 3,200 suspected militants.
AGENCE FRANCE-PRESSE, DPA