The ‘tinderbox’ Middle Eastern borderlands where US troops faced attack

For years, Arab and western officials have kept a watchful eye over an arid tract of land in a remote corner of the Middle East, where US troops, Iran-linked militias and the remnants of Isis all operate.

Tehran-backed militants sit at checkpoints and makeshift bases along the strategically important Baghdad-Damascus highway, which they long ago seized — the epicentre of a highly prized smuggling network in the border triangle, a centre for drugs and weapons trafficking by militants and criminal gangs.

On Sunday, this corner between Jordan, Syria and Iraq became the latest flashpoint in the widening regional hostilities that have drawn the US back into combat.

A drone attack on a small US base in north-east Jordan known as Tower 22 killed three US soldiers and injured dozens more, becoming the first such assault to kill American troops since the Israel-Hamas war increased tensions across the region. Washington blamed “radical Iran-backed militant groups” and vowed to hold those responsible to account. 

“That area has long been a tinderbox,” said a senior western diplomat in the region. “We’ve always been worried about US and Iranian forces getting into direct confrontation there, whether by accident or on purpose.”

The attack underlined the threat to US interests from Iran-backed militants and the challenge facing President Joe Biden in seeking to counter their attacks while avoiding being drawn into a full-blown regional war.

The US has about 3,000 troops across Jordan, a longtime ally. But American troops are at their most vulnerable in Iraq and Syria, where they are surrounded by hostile factions. As part of the US-led coalition fighting Isis, the US has maintained 2,500 troops in Iraq and 900 more in Syria, mostly in the north-east, an area controlled by Kurdish groups.

Yet these countries, where the US has been engaged in tit-for-tat escalation with Tehran, are the most likely staging grounds for Biden’s retaliation. Syria is largely seen as the easier of the two in which to launch attacks, as the US does not maintain relations with Bashar al-Assad’s regime, another ally of Iran. 

Washington must tread more carefully in Iraq, which now presents the Biden administration with one of its most acute challenges in the region.

Twenty years on from its invasion of the country, US influence is waning in Iraq, overshadowed by Tehran, which now wields unrivalled influence over Baghdad’s ruling elite. 

Since the 2020 assassination of Iran’s most powerful commander Qassem Soleimani, Tehran and its closest allies have vowed to push the Americans out of Iraq for good, and have turned the country into a hotbed of anti-American militancy. 

While Iran publicly distanced itself from Sunday’s attack, there was little doubt that a group within its regional network of proxies was responsible.

A shadowy group known as the Islamic Resistance of Iraq has taken credit for more than 140 attacks on US troops in Iraq and Syria since October 17, including one earlier on the same day on al-Tanf base in Syria, which lies about 20km away from Tower 22. 

Such Iran-backed militia groups, known collectively as the Hashd al-Shaabi, have risen in Iraq to become powerful military and political forces with tens of thousands of fighters. Their influence rose significantly after they played a role countering Isis’s blitz across Iraq in 2014, in parallel with the US-led coalition’s efforts, despite being firmly on opposing sides. 

Some armed groups are now partially integrated into state institutions, their leaders holding influential positions within the governing coalition and maintaining historic links with Iran.

These tend to be older and more established groups that have political wings, patronage networks and maintain a strong social base, from which they draw their members. These groups tend to have a more domestic agenda driven by political and economic interests, said Renad Mansour, the director of Chatham House’s Iraq initiative. 

Others, which are closer to Iran’s Revolutionary Guards and Lebanon’s Hizbollah militant group, “should be understood as transnational and are seemingly designed for this kind of regional conflict”, said Mansour, who is leading research on this cross-border conflict.

“These resistance groups are not interested in national politics or governance. They see their role as part of a broader conflict against the US and Israel,” which they attack whenever tensions flare up between the US and Iran, he said.

Both groups have long opposed the presence of US troops in Iraq, and their collective pressure on Iraq’s prime minister recently triggered renewed talks between Washington and Baghdad about the future of the US-led coalition’s presence in Iraq. A first meeting between officials from both capitals took place just 24 hours before Sunday’s deadly attack.

But they are somewhat divided in their approach: the more establishment groups are wary of turning Iraq into another pariah state like Iran — a situation that would cut them off from international markets, diplomacy and their critical US dollar supply. 

“This is the line being pushed by [Iraqi premier] Sudani and those establishment groups who understand that Iraq benefits from good relations with Washington, as does Iran,” Mansour said. 

That line is being challenged by the groups closer to Iran who are pushing to eliminate the US presence in Iraq altogether, guided by the more extreme factions in what Tehran calls the axis of resistance, who have vowed revenge.

While there had been few anti-American attacks for most of 2023, the Israel-Hamas war provided them with an excuse to break that truce.

In the face of attacks by the Islamic Resistance of Iraq, US forces have retaliated with a handful of air strikes, including one in Baghdad that killed a senior commander in an Iran-aligned militia in Iraq earlier this month.

Washington faces a challenge in calibrating its next response amid its intensifying stand-off with Tehran, whether the killing of the three US troops was deliberate or a miscalculation, said Rym Momtaz, a consultant fellow at the IISS think-tank.

“The Biden administration’s retaliation cannot be along the lines of the tit-for-tat that has occurred over the past three months,” Momtaz said. “It now needs to restore escalation dominance and deter the ability of the Iran-backed armed groups in the region to attack US troops, at least for the foreseeable months.”

Washington has also sought to use financial levers to push Baghdad to help curb Iranian sanctions evasion and funding for militant groups; this week it imposed sanctions on the owner of Iraq’s Al-Huda Bank, accusing the bank of serving as a conduit for terrorist financing.

The Biden administration has been keen to wind down its troop presence in the Middle East. But reluctant to be seen as withdrawing under pressure from militant attacks, it has insisted that talks about its presence in Iraq were not related to the recent escalation.

However, Sunday’s attack crossed a red line and may force Washington to reassess this withdrawal, the senior western diplomat said.

“The last time a US contractor was killed in 2019, [former president Donald] Trump assassinated Qassem Soleimani.” There must be a robust response to Sunday’s strike, he said, “or Biden will be sending a message to Iran that it is weak and has been deterred.”