The fight to wrest a desert area in eastern Syria from the “Islamic State of Iraq and Syria” (ISIS) will take "much longer than expected", the Syrian Democratic Forces told AFP on Tuesday (October 16th).

The reassessment came as the UN warned that the fight for Hajin in Syria's eastern province of Deir Ezzor was having a "devastating" effect on thousands of civilians.

The Arab-Kurd alliance has been locked in clashes for just over a month with ISIS holdouts in Hajin and surrounding villages, but they have been slowed down by harsh weather conditions and a ferocious extremist fightback

"The military operations in Hajin will take much longer than expected," said Redur Khalil, a top SDF commander. "ISIS is benefiting a lot from weather factors, including sandstorms. They have helped it take cover from reconnaissance aircraft and other monitoring mechanisms.”

Khalil said the area around Hajin was vast and arid, "larger than just a pocket".

The SDF estimates some 3,000 ISIS fighters are defending the area, and have laid a massive network of trenches, barriers, and explosives to hinder the SDF's advance, Khalil said.

"Most of the fighters in the Hajin region are foreigners with fighting experience," he added.

Hajin is one of ISIS's final holdouts in Syria.