Syria Weekly: Is a Saudi-Iran proxy war brewing?
The move to reach out to traditional tribal allies in the SDF followed the UAE's own efforts to befriend the US-backed militia force, a remarkable partnership given the Marxist outlook of the Kurdish faction that dominates it.
Despite the obvious ideological differences, what unite all three parties are their shared suspicions of Turkey and Iran, two key powers with expansionist agendas in Syria.
Saudi Arabia-UAE have been keen to keep in check Turkish and Iranian territorial aspirations in Syria, and over the past year have steadily increased their presence in SDF-controlled areas in the north and east of the country, particularly through aid.
With it now clear that Bashar al-Assad won't be easily coaxed out of Iran's sphere of influence, Riyadh and Abu Dhabi undoubtedly see the Kurdish-Arab tribal coalition as an obvious partner in Syria.
The SDF - with a hostile Turkish-Syrian rebel force to their west and Iranian militias to the east - are eager for allies, particularly after Donald Trump's erratic pronouncements about a full US-disengagement from Syria, a move that would leave the Kurdish-Arab force friendless and vulnerable to attack.
Saudi Arabia, with its historical links to Arab tribes in the east - many of which are part of the SDF - are increasingly eager to halt the spread of Tehran and Ankara's influence in Syria, following the defeat of the Islamic State group.
To achieve this, Saudi Arabia appears willing to throw some support behind the SDF to achieve this goal.
This included a pledge last year by Saudi Arabia to invest $100 million in SDF territories around Raqqa, but analysts believe that a more solid alliance is in the making, particularly as it is increasingly clear that Riyadh and Washington are not willing to confront Iran directly.
If attacks on Saudi and US interests by Iran continue the two countries might look at other ways of hurting Tehran's interests in the region.
Blocking the proliferation of Iran's powerful militia force in eastern Syria would be one way of acheiving this and Riyadh's relationship with Deir az-Zour's tribes could make it a useful partner in any attempt by the US or Israel to disrupt Tehran's territorial aims.
Shortly after suspected Iranian strikes on Saudi oil infrastructure on Saturday, a leader of the pro-regime Al-Baqir Brigades militia in Deir az-Zour, eastern Syria, publicly vowed to take back all territories held by the SDF in Syria.
|The people in those areas categorically reject the return of the Assad regime, the militias of Iran and Daesh
- Omar Abu Layla, director, Deirezzor 24
The Iranian-aligned brigade also issued an apparent threat to the local populations of the east - who are deemed, by many, to be hostile to Assad - sparking spontaneous protests in regime-controlled areas against Tehran's influence in the region.
Omar Abu Layla, director of the Deirezzor 24 monitoring site, told The New Arab that the protests were a direct response to the pro-regime brigade commander's threatening language.
Other Arab tribes in SDF-controlled areas of Deir az-Zour have also voiced their fears about a possible Iran-Syria regime offensive on their towns, he said.
Clashes between protesters and the Tehran-linked militia - which controls much of Deir az-Zour - erupted and resulted in at least three deaths, according to the Syrian Observatory for Human Rights.
It marked the most intense period of unrest in regions taken by the regime from IS and has sparked a brutal response from the militias. Two bodies of suspected protesters were found over the weekend, showing signs of torture, according to opposition media.
"The demonstrations were held by people who don't belong to any military party or others [and] came in response to the Iranian militia's threats to storm the eastern Euphrates areas," Abu Layla told The New Arab.
"The people in those areas categorically reject the return of the Assad regime, the militias of Iran and Daesh [the Islamic State group], so their message was clear regarding that."
Maher al-Assad, Bashar's brother, has been a target of the protesters' ire, due to his close relationship with Tehran and the dominant role he plays in the regime's military apparatus.
Some analysts have told The New Arab that the regime's army can no longer be considered a conventional and centralised military force, but now consists of a myriad of militias - as loyal to Iran's Revolutionary Guards and their Syrian proxies as they are to the Syrian president.
Signs of a possible wider anti-regime insurgency breaking out in Deir az-Zour have been suggested following events over the past few days.
With unrest also brewing in Daraa and the regime still unable to break-through in rebel-HTS-held Idlib, the unrest in Deir az-Zour will undoubtedly be worrying officials in Damascus, particularly if eastern rebels were to receive foreign backing.
Abu Layla said that although the protests are unrelated to the Saudi minister's visit to Deir az-Zour, Riyadh might see this as a ripe moment to rekindle its relationship with local Arab tribes and re-engage in Syria, having effectively cut support for anti-Assad Syrian rebels some years ago.
"The Saudi minister's visit has restored the relations and renewed the confidence of the local community in Deir ez-Zour to strengthen the relationship with Saudi Arabia as both have [long] relations and are threatened by the same enemy," he said.
Both Riyadh and some members of the tribes are said to be eager to confront Tehran in Syria, after Iran was able to expand its influence in the country almost unchecked - particularly in the strategically-important and resource-rich eastern regions.
"It is quite normal for Saudi Arabia to stand with any party hostile to Iran, whether in Syria or outside it. In my opinion, Saudi Arabia will not hesitate to provide any kind of support to the region for the purpose of expelling the Iranians and the [Tehran-linked] militias," Abu Layla added.
Far away from Damascus, Tehran has stamped its authority on Deir az-Zour, where its foreign militias have come to dominate the security apparatus.
Iranian military bases have been set up, including a local headquarters in the border town of Albukamal - situated in a good position to watch over a potential transit route between Tehran and Damascus.
|The area to the east of the Euphrates seems to be the last stronghold for Saudi influence in Syria
- Haian Dukhan, author of State and Tribes in Syria
The fact that the Iranian bases in Albukamal - on the Syria-Iraq border - have become frequent targets of Israeli fighter jets (along with unverified reports of Saudi strikes this week) then the strategic importance of Deir az-Zour is now being taken seriously by regional powers opposed to Tehran.
Abu Layla said that anger is also growing among the people of Deir az-Zour about the harsh rule of the Iranian-Syrian regime security forces, militia recruitment drives, and endeavors by Iran to spread Shia Islam in what is a predominantly Sunni region.
Efforts to co-opt the tribes by Tehran are not new, and there have been reports of numerous attempts by Iran to recruit groups in Syria's eastern regions, including Raqqa, through missionary activities before the war.
Bashar and his father Hafez, have also attempted to mould Deir az-Zour tribal leaders in eastern Syria, through special privileges into good regime loyalists, with mixed results.
Abu Layla said the strong backing for the Free Syrian Army in the early years of the revolution in eastern Syria highlights the failure of this policy.
One group that have backed Assad during the war are elements of the Al-Baggara, one of Deir az-Zour's largest tribes.
They have dominated the pro-regime, Iran-backed Al-Baqir Brigades militia force and although Sunni, a few thousand members of the tribe are thought to have converted to Shia Islam.
Riyadh will be able to benefit from the majority of tribes of Deir az-Zour remaining hostile to the regime, Abu Layla said.
Many of the tribes' sheikhs live outside regime control in Turkey, the Gulf, and SDF territories and could be willing to confront Assad and his Iranian allies.
Haian Dukhan, a UK-based Syrian academic and author of State and Tribes in Syria, also agrees that Saudi Arabia has used its close relationship with tribes to carve out influence in eastern Syria, particularly after the region fell into opposition hands in 2012 and 2013.
"Saudi Arabia has tried to use some of the Syrian tribes as its proxies in the Syria conflict. It has strong ties with members of the Egidate tribe in Deir az-Zour and large members of this tribe live in Saudi Arabia, some of them have been naturalised and have dual Saudi-Syrian citizenship," he told The New Arab.
He said that Riyadh has started to use its connections with these tribes to resist the spread of Iranian influence in the region, following the defeat of IS.
"Iran has more of less managed to enable the regime to conquer most areas that were taken by the Saudi-backed rebels," he said.
"The area to the east of the Euphrates seems to be the last stronghold for Saudi influence in Syria. If they were to fall it would mean Iran would have full control of Syria."
Dukhan said that Iran continues to tighten its rule in the east and use soft power initiatives to win over tribes, particularly elements of the Al-Baggara.
Despite this, a relative stalemate exists between the SDF and regime on the frontlines in Deir az-Zour, but things may be about to change.
"So far things have been relatively quiet on both sides of the Euphrates River. The focus was on trying to defeat IS but now they are defeated and tensions are rising in the Gulf things might extend to Syria, where each side will use tribal militias to create tensions."
Paul McLoughlin is a news editor at The New Arab.
Follow him on Twitter: @PaullMcLoughlin