BEIRUT (Reuters) - The U.S.-backed Syrian Democratic Forces will soon seize the town of Hajin from Islamic State (IS) in eastern Syria near the Iraqi border, a spokeswoman said on Friday.

Hajin is the last big town Islamic State holds in its remaining enclave east of the Euphrates River. The SDF, spearheaded by the Kurdish YPG militia, has battled to eliminate the jihadists there for several months.

“Military operations are ongoing to fully end Daesh ... our forces are advancing in fierce battles,” Lilwa al-Abdallah, spokeswoman for the offensive in eastern Deir al-Zor province, said using an Arabic acronym for Islamic State.

“Soon, we will celebrate the full liberation of Hajin from the hands of the mercenaries.”

A YPG source said the SDF was now in control of Hajin, where some small remaining pockets of IS resistance would be finished off in the next day or two.

After losing Hajin, Islamic State will control a diminishing strip of territory along the eastern bank of the Euphrates River in the area where U.S.-backed operations are focused.

The jihadists also control some desert terrain west of the river in territory otherwise controlled by the Damascus government and its allies.

SDF commander-in-chief Mazloum Kobani told Reuters on Thursday that at least 5,000 IS fighters remain holed up in the pocket of territory including Hajin and that they had decided to fight to the death.

This included some 2,000 foreign fighters, mostly Arabs and Europeans along with their families.

Kobani also said it was possible that Islamic State leader Abu Bakr al-Baghdadi was in eastern Syria, but the SDF could not be sure because he often drops from sight.

Islamic State lost nearly all the territory it once held in Syria last year in separate offensives by the U.S.-backed SDF on the one hand, and the Russian-backed Syrian army on the other.

Syria’s main Kurdish parties warned on Friday that Turkish threats to attack the SDF region in northern Syria amounted to a “declaration of war” and urged world powers to prevent an assault.