GENEVA: More than 23,000 refugees fleeing fighting in northern Syria have crossed into Turkey, the United Nations refugee agency said Tuesday, quoting Turkish authorities.

Syrian Kurdish-led forces said they had captured a town at the Turkish border from ISIS Monday, driving it away from the frontier in an advance backed by U.S.-led airstrikes.

"Most of the new arrivals are Syrians escaping fighting between rival military forces in and around the key border town of Tel Abyad, which was controlled by militants and faces Akcakale across the border," UNHCR spokesman William Spindler told a Geneva briefing.

Some 70 percent are women and children, he said.

"UNHCR field staff say most refugees are exhausted and arrive carrying just a few belongings. Some have walked for days."

The figure includes more than 2,183 Iraqis from the cities of Mosul, Ramadi and Fallujah, Spindler added.

U.S. and coalition forces are also conducting air strikes targeting ISIS in Iraqi cities.

Turkey now hosts more than 1.7 million registered Syrian refugees, "more than any other in the world," Spindler said.