They felt they had found an international sponsor in the United States, which relied primarily on the fighters of the Kurdish People's Protection Units (YPG) to roll back IS in northern and eastern Syria.

But with IS holding just five percent of Syria, Kurds worry the US could withdraw support, costing them the key political and territorial gains they scored in the chaos of war, AFP reported.

Qamishli is the main hub of the autonomous administration the Kurdish authorities have run since Syrian forces withdrew from swathes of northeast Syria in 2012.

In March 2016, Kurdish parties announced they would seek to establish a federal system there after ousting IS from much of the area with the help of the US-led coalition.

Their biggest win was Raqqa, once IS's de facto Syrian capital but captured in October by the YPG-led Syrian Democratic Forces (SDF).

Weeks later, the US announced it was pulling 500 Marines from its nearly 2,000-strong force in Syria and "amending" its support to the YPG.

But the jihadists are "not finished yet," said Nassrin Abdallah, a commander in the group's female branch, the Kurdish Women's Protection Units (YPJ).

Sleeper cells still stage attacks and IS militants are active in the eastern province of Deir Ezzor, she said.

"It is important for the coalition forces to stay to guarantee security and stability, since the threat from Daesh still exists," Abdallah added, using the Arabic acronym for IS.

"Turkey is also a threat to the Kurdish people," she said.

Reporter’s code: 50101