In the early hours of Monday morning, US airstrikes targeted Iran-backed militia groups at Albu Kamal in Syria and Al Qaim, a small town just across the border in Iraq.
The airstrikes, Pentagon spokesman John Kirby said, were “defensive” and targeted drone storage sites, blowing up explosive “unmanned aerial vehicles”.
Mr Kirby also named the militia groups singled out for attack: Kataib Hezbollah and Kataib Sayyid Al Shuhada, both factions in a militia umbrella organisation linked to the Iraqi state, the Popular Mobilisation Forces, or PMF.
The groups suffered four killed, according to a statement issued by the PMF on Monday.
Both of the militias were given Iraqi state backing in 2014 following an executive order by then PM Nouri Al Maliki, but they had both existed before then, with Kataib Hezbollah fighting US forces in Iraq between 2007 and 2011.
Kataib Sayyid Al Shuhada is thought by some analysts to have been formed to fight in Syria in 2013, alongside Iranian advisors.
The militias become official
In 2014, Iraq’s army was crumbling in the face of a ferocious ISIS advance and, following PM Maliki’s executive order, the revered Shiite cleric Grand Ayatollah Ali Al Sistani issued a fatwa calling on all young Iraqis to join the security forces.
That was a blessing for Iran-backed militias, who used Al Sistani’s fatwa to boost their ranks. Other militia groups were also formed who did not answer to Iran, and are now directly linked to the Iraqi state, such as the Abbas Combat Division.
But the Iran backed groups soon took over the PMF.
Many of those groups support Iran’s system of religious rule, or Guardianship of the Jurists. Sistani, on the other hand, wants Iran to remain a democracy.
These differences have become a major challenge for the Iraqi government, which also wants to remain allied to the US, and has a regular army alongside the PMF.
Many of the PMF groups also stand accused of using murder and intimidation to suppress Iraqis opposed to Iran’s agenda in Iraq, and the Iraqi government has struggled to hold the killers accountable.
Before receiving official Iraqi support through the PMF, Kataib Hezbollah were part of a Shiite insurgency against US and other coalition forces after the 2003 Iraq invasion.
The militia, according to specialist Hamdi Malik at the Washington Institute for Near East Policy, was selected by Iran as the vanguard of anti-US operations.
Specialised Iranian support made them increasingly lethal. In 2011 for example, the group killed 15 US soldiers in the space of a month, even as US forces were in the process of leaving Iraq.
Designated a terrorist organisation by the US in 2009, the group and their leader Abu Mahdi Al Muhandis soon garnered a vicious reputation. Al Muhandis was killed in a US airstrike in 2020, along with Iranian General Qassem Suleimani.
Since then, the group, along with other PMF groups such as Kataib Sayyid Al Shuhada have escalated attacks on US forces, expanding their strategy to using highly targeted drone strikes with equipment supplied by Iran.
Washington seems to have acted to send a warning signal for the groups to stop drone operations.
But heavy US airstrikes against these PMF groups have not deterred them in the past. Only time will tell if Iran and the US can break their current cycle of escalation and counter strike in Iraq.