More than 2,000 people including dozens of "Islamic State of Iraq and Syria" (ISIS) fighters left the group's final holdout in eastern Syria in the past 24 hours, AFP reported Wednesday (January 16th).

The Syrian Democratic Forces (SDF) are waging a final assault on the area east of the Euphrates river and have provided buses to evacuate civilians and fighters trapped inside.

"In total, 2,200 people have left in the last 24 hours, including 180 ISIS fighters," the Syrian Observatory for Human Rights said.

Travelling in private cars and buses provided by the SDF, they were headed for camps run by the SDF, Observatory head Rami Abdel Rahman said.

The SDF, backed by airstrikes from the international coalition, in September launched an offensive to oust ISIS from the rump of the once-sprawling "caliphate" it proclaimed in 2014.

Abdel Rahman said over 20,000 people have fled the area since the start of December, including Syrian, Iraqi, Russian and Somali fighters.

He said the outflow of evacuees had accelerated in recent days, with some 5,300 people including 500 ISIS fighters leaving since Friday.

Thousands of people had already fled on foot before that.