Rojda Felat, a Syrian Democratic Forces (SDF) commander, waves her group's flag at the iconic Al-Naim square in Raqa on October 17, 2017

Syria's Kurds fear the steadfast ally they found in the US to successfully take on Islamic State group jihadists may now leave them to face threats from Turkey and Damascus alone.

Across Syria's north, Kurdish authorities have spent more than four years steadily building public institutions including elected councils, security forces, even schools.

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.

"We are afraid of America, which has been using us as a card to play for a long time," said Rafea Ismail, a 37-year-old who sells women's accessories on the hood of his car in the city of Qamishli.

"When they're done using us, they'll forget us," he said.

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

"All countries should support us because we fight terrorism. We liberated Raqa, and America should not abandon us and ally with Turkey," said Nawal Farzand, a 45-year-old Kurdish language teacher.

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 Raqa, once IS's de facto Syrian capital but captured in October by the YPG-led Syrian Democratic Forces.

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 militia's female branch, the Kurdish Women's Protection Units (YPJ).

Sleeper cells still stage attacks and IS fighters 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."

- 'Gravest' danger is Turkey -

The Kurds' rising profile had enraged Damascus, which insists it wants to recapture every inch of territory lost since Syria's uprising erupted in 2011.

But it especially alarmed Turkey, which feared the semi-independent administration in northern Syria would inspire similar ambitions among its own Kurdish community.

Ankara considers the YPG as "terrorist" because of its ties to the outlawed Kurdistan Workers' Party (PKK).

English teacher Nada Abbas says she, too, fears the US "will abandon the Kurds after the end of the battle against Daesh."

"This would be a gift to Turkey, which doesn't accept Kurds becoming stronger," says the 30-year-old.

"It would attack us like it did in the past. The Turkish threat will not end," Abbas adds.

Nicholas Heras, a fellow at the Centre for a New American Security think tank, says Turkey poses "the gravest threat to the Kurds in Syria" -- even more than Syrian President Bashar al-Assad or IS.

Turkish President Recep Tayyip "Erdogan has made it crystal clear that as soon as the Americans are no longer in the way, he intends to crush the Syrian Kurds, all of whom he views as PKK," Heras tells AFP.

- 'Russia is the insurance policy' -

Fears of an American withdrawal may be drawing Syrian Kurds into Russia's orbit.

The YPG recently announced that its anti-IS operations in east Syria had received air support from Moscow.

Russian forces have also trained Kurdish fighters further west in Afrin -- where there is no IS presence -- and manage a buffer zone between Kurds and Turkish-backed rebels.

And Moscow has been particularly outspoken in support of Syria's Kurds having a seat at the negotiating table at talks in Geneva.

"The relationship between the YPG and the Russian military is becoming a special one. The Syrian Kurdish region of Afrin is solely dependent on the Russian military, not the Americans, for protection from Turkish attack and occupation," says Heras.

Syria's Kurds may seek to protect themselves from Turkey by leveraging relationships with both Russia and the US.

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