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Sunday’s drone attack on an isolated US outpost in Jordan called Tower 22, which killed three US soldiers, has highlighted America’s lingering presence in the region six years after the near total defeat of ISIS.
The base is one of several established by the Americans to counter ISIS after 2015, when small contingents of US special forces entered Syria, teaming up with beleaguered Kurdish militias to fight the terrorists.
Unlike the largest coalition base in western Iraq, Al Asad, which is well protected, Tower 22 and six similar sites in Syria are comparitively vulnerable.
Sites such Al Tanf in Syria, which is not far from Tower 22, Conoco, near an old oil and gasfield on the Euphrates, and another known as Green Village nearby are remote and harder to resupply.
Their isolation has made them a tempting target for several enemies, from Iran-backed Iraqi militias to Syrian and even Russian forces in Syria, including mercenaries.
What is Tower 22?
Tower 22 has been described as a logistical support base for the nearby US Al Tanf garrison, hosting about 350 US soldiers and Air Force personnel.
It exists in a “deconfliction zone” in the Iraq-Syria-Jordan border area, established in a shaky 2016 agreement between the US and Russia.
During the Syrian civil war, Al Tanf was used for training Syrian opposition fighters, some of whom fought against President Bashar Al Assad, although the US had said their focus would be on countering ISIS.
US forces are also stationed alongside Syrian Kurds far to the north-east of Al Tanf, in Hasakah, among other small outposts in Kurdish-controlled areas.
Mr Al Assad sees the US presence as a thorn in his side, with Kurds controlling what remains of Syria’s battered oil industry in the east, although much of the energy infrastructure has been bombed by Turkey, which opposes the US-allied Kurds, having already been heavily damaged during the ISIS war.
Syria’s ally Iran views the bases as a project to halt missile and drone transfers to Syria and Hezbollah in Lebanon, because several of the bases are on transport stops on Syria’s border with Iraq.
It’s this combination of factors that makes the area such a flashpoint amid heightened tensions linked to the Gaza war.
Three US troops killed in Jordan drone attack
Iran war risk
The attack calls into question whether America’s decades-long stand-off with Iran has entered a dangerous new phase, after years when Washington and Tehran’s allies clashed but often backed off from full-scale war.
“That’s certainly a risk,” said Raphael Cohen, an analyst specialising in US air power with the Rand think tank.
Iran-backed militias clashed with US forces during their presence in Iraq between 2003 and 2011, and from 2014 to the present. But the clashes in Syria are relatively new, beginning in 2017.
Iran’s proxies, including a number of militias on the Iraqi government payroll as part of an organisation called the Popular Mobilisation Forces, were behind most of the attacks.
Amid the Gaza war, parts of the PMF, such as Kataib Hezbollah and Harakat Hezbollah Al Nujaba, have claimed to support Palestine against the US and Israel, worsening tensions.
“The fact that these groups haven’t killed Americans from October 7 until now is more a testament to American air defences and frankly lots of good luck, rather than a lack of intent,” Mr Cohen told The National.
“At the same time, it seems to me that this latest attack and the 170-plus ones that preceded it demonstrate that Iran and its proxies are already intent on escalating," he says, citing Washington Institute for Near East Policy data.
Michael Knights, an expert on the militias at the Washington Institute for Near East Policy, said: “Iran is running out of rungs on the escalation ladder."
“Many of the obvious options are opportunity-limited, meaning not available to hit right now,” he said, referring to possible US strikes, and “opportunity targets” that can include militia commanders on the move.
“So that may skew us towards fixed targets that we have been eyeing for a while, with an Iranian flavour, possibly inside Iran.”
The latter would be almost unprecedented, although the US and Iranian navy clashed violently in 1988 during the Iran-Iraq War, and 32 years later Maj Gen Qassem Suleimani, commander of the Islamic Revolutionary Guard Corps’ Quds Force, was killed by Americans forces.
Both clashes took Washington and Tehran to the brink of war.
Driving the US out of Syria
Iran’s efforts to push US forces out of Syria have largely failed – including a February 2018 clash at the Conoco outpost. The base was attacked by Iran-backed Afghan, Pakistani and possibly Iraqi militias, alongside Russian mercenaries and Syrian troops. Massive US air strikes stopped the assault.
That has not deterred the Iran-backed militia Kataib Hezbollah, which controls the PMF’s drone force and has admitted moving “powerful” weapons across the border, claiming to have used ballistic missiles against US forces in Iraq and drones in Syria, under the banner of the “Islamic Resistance in Iraq”.
Kataib Hezbollah's commander Abu Mahdi Al Muhandis was killed alongside Maj Gen Sulaimani in the air strike on Baghdad in 2020 and the militia has been fighting a low-level conflict with the US since.
The US has managed to repel most drone and missile attacks launched by militias but some have managed to evade sophisticated American anti-drone systems and hit their targets.
In January last year, for example, one US soldier was killed at Al Tanf, prompting US air strikes, while two months later a contractor was killed by a drone “of Iranian origin” at Hasakah, leading to more bombing.
How many US troops are still in Syria?
About 900 US soldiers are thought to remain in Syria, compared to 2,500 US forces in Iraq, training domestic officers. The US presence in Iraq could end following calls from Prime Minister Mohammed Shia Al Sudani for them to exit.
Until then, the US has to weigh up options for a counterstrike that will punish the militias without starting a major war.
“I’d expect a more forceful response from the Biden administration than in the past,” Mr Cohen said.
“This attack, after all, killed three Americans and wounded dozens more. That can’t go unanswered. A lot of Congressional leaders, mostly on the Republican side, are pushing for a more forceful response, too, so there is a political logic here.
“The question is really what form it takes and whether we target just the proxy group itself or their Iranian backers, too, as some senators are calling for.
"To date, the Biden administration has thus far tended to be cautious, perhaps to fault, when it comes to these actions," Mr Cohen added. "As such, the administration’s first instinct will be to keep it limited, but the fact that Americans were killed here changes things, so it may depend on what the intel says about how closely the Iranians were involved.”
