As the 1,500 delegates made their way to the Russian city of Sochi to attend a conference billed as a first step to peace talks in Syria, one major power broker was absent: the US.

The Sochi peace talks, brokered by Russia, Turkey and Iran, collapsed and Syria took another bloody turn in its intractable conflict. Few in the Syrian opposition have the illusion that they or the regime of Bashar al-Assad have a say in what will happen next.

But even as those three powers, with boots on the ground, contemplate their next move, the US has quietly built up its presence in northern and eastern Syria, a military force augmented by proxy Kurdish and Arab militias as well as a nation-building exercise in areas liberated from Islamic State.

They have carved out a stretch of territory east of the Euphrates and south towards the Iraqi border, just as the other regional powers have done. Turkey and its proxies now control the area north of Aleppo, while Russia and Iran jockey for influence in central Syria and close to the Israeli border.

A Syrian Democratic Forces (SDF) fighter checks for enemy movements during the liberation of Raqqa from Isis. Photograph: Achilleas Zavallis

But while the US presence has reassured allies such as Saudi Arabia and Israel, which backs that long-term presence in the area, it has further alarmed Turkey, which fears the US reliance on Kurdish militias to lead such an effort will harm Turkish border security.

It also risks solidifying the divisions within Syria, carving out a space beyond the control of any future Syrian government and under an American security umbrella, making the prospect of a peace settlement and a unified Syria farther away than ever before.

“The broader outlines are there,” said a Syrian source who works with the US in Raqqa province, once the capital of Isis in Syria.

“A political solution in Syria will be in the form of a deal between states, where the Americans agree with the Russians and Turks and Iranians and the Gulf countries on who will retain influence in the various regions,” he said. “Once the cake is divided, there will be a political solution in Syria.”



Once the cake is divided, there will be a political solution in Syria. Syrian source

Rex Tillerson, the US secretary of state, outlined Washington’s strategy last month in a speech in California, saying the US presence would counterbalance Iran, continue to battle remnants of Isis as it retreats into desert hideouts, “stabilise” areas liberated from the Islamist group and support local civilian administrations. He hinted the presence would be long term, to ensure the mistakes the US made in Iraq would not be repeated and prevent a re-emergence of Isis.

Two US F-22s flying above Syria in support of Operation Inherent Resolve earlier this month. Photograph: Colton Elliott/US air force/EPA

In recent days the Pentagon released its planned 2019 budget, which envisions a troop presence of about 6,000 US soldiers as part of the coalition against Isis in Iraq and Syria. In Iraq, Washington is drawing down its presence as parliamentary elections approach in May.

To carry out those objectives, the US has allied itself on the ground with the Syrian Democratic Forces (SDF), an alliance led by the Kurdish militia led by the People’s Protection Units (YPG). That partnership has enraged Turkey, which considers the YPG the Syrian wing of the Kurdistan Workers’ party (PKK), a designated terrorist group that has fought a decades-long insurgency against the Turkish state.

Ankara believes the YPG is taking advantage of the US security umbrella to carve out an autonomous zone, or an independent state, along the border with Turkey. It also worries the US will continue that alliance as Washington seeks to rebuild and stabilise those parts of Syria the YPG controls and to prevent Iran’s growing influence in the Middle East.

For a lot of US officials, and some in Gulf countries, the main issue in the Middle East is to stop Iran, at all costs. Senior Turkish official

“For a lot of US officials, and some countries in the Gulf, the main issue in the Middle East is to stop Iran, at all costs,” said a senior Turkish official. “So this Iran, Iran, Iran emphasis or obsession drives them into this kind of policy. Syrian territory is becoming just a scene for this proxy war.”

But the US has continued to work with the SDF, rebuilding bridges, clearing mines and repairing infrastructure, while placing Kurdish officials in key local administrative posts. It has also continued to provide political and military support to the alliance.

“The cooperation of the SDF with the [US-led coalition] in the north is known,” said Sepan Hamo, the overall commander of the YPG. “It is a starting point for combating Daesh [Isis], which began in Kobani, and continued to Deir ez-Zor.

“There are also relations with the political administrations, there is coordination and joint work in reconstruction and management efforts. We have no aspirations or problems with the people of those areas.”

A Turkish tank fires during an operation near Afrin, Syria, on Monday. Photograph: Anadolu Agency/Getty Images

That cooperation has continued to alarm Turkey, which launched an operation last month in the Kurdish enclave of Afrin against the YPG, and threatened to afterwards attack Manbij. The impetus came after an announcement that the US would build a 30,000-strong border force to patrol Syria’s frontiers against Isis.

As the US establishes its presence in yet another Middle Eastern adventure, it has ingrained itself as part of the problem and the solution in a Syria torn in a great power struggle.

“When you are in this kind of battle with different great powers playing this game over Syrian territories, there won’t be an end to the war in Syria, at least for years to come,” said the senior Turkish official.