Iraqi Prime Minister Mustafa al-Kadhemi will meet US President Donald Trump for the first time in Washington on Thursday, with the presence of American troops in the country at the top of his agenda.
The meeting comes as attacks on American targets by pro-Iranian fighters have been on the rise, and with Tehran and Washington competing for influence in Iraq, the gulf between pro-Iranian factions and Baghdad's US-friendly premier is growing.
Kadhemi, who took office in May, faces challenges from factions of the Popular Mobilization Forces (Hashed al-Shaabi), a coalition of Iraqi Shiite paramilitary groups with close ties to Iran.
The PMF is officially integrated into the Iraqi state, and its political representatives have called for the expulsion of the 5,000 US troops deployed in the country as part of anti-militant efforts.
US Secretary of State Mike Pompeo said Wednesday that "armed groups not under the full control of the prime minister have impeded our progress," calling for them to "be replaced by local police as soon as possible."
Pompeo -- who was speaking at a press conference with Iraqi Foreign Minister Fuad Hussein -- appeared to be referring to Shiite paramilitary groups, though he did not identify them by name.
Asked about the plan for cutting the 5,000 US troops now in Iraq, Pompeo said he had no numbers and urged people "not to focus on that."
On the troop issue, a senior administration official said: "There are no hard fast timelines, and there are no hard fast numbers but that certainly would be part of the discussion, as we evaluate what Iraq security requirements are, and what the United States believes it can do."
The official described "armed groups" as "a persistent problem that challenges Iraqi security, has threatened US forces' interests in the region, and certainly it's a challenge to Iraq sovereignty."
"We think that Iraq's internal security needs are best met by forces that are, first and foremost, under the sovereign control the government of Iraq," the official said.
Pro-Iranian factions were hit hard by Washington's assassination in January of one of their top chiefs, Abu Mahdi al-Muhandis, in a strike that also killed top Iranian commander General Qasem Soleimani.
- Attacks on the rise -
The PMF denies any connection to a recent spate of anti-US attacks, but videos and claims on social media hint at its involvement, through groups operating under other names.
Kadhemi has angered armed groups by seizing border posts where they ran lucrative smuggling networks and imposed taxes on traders.
Attacks have risen in recent weeks, with the Iraqi army reporting another rocket attack on Tuesday evening targeting Baghdad airport, where US troops are based. The projectile did not cause damage or casualties, the army said.
From October to the end of July, Iraqi armed factions carried out 39 rocket attacks against American interests in the country.
But after the White House earlier this month confirmed that Trump would meet Kadhemi, the pace intensified.
Between August 4 and 18, 14 bomb and rocket attacks targeted Iraqi logistics convoys for the US military, bases housing US soldiers, and the US embassy.
While the impact has been limited, the attacks have served as a show of strength.
After an attack on a convoy in Iraq's south, a man was arrested in possession of bombs and a PMF military ID card that allowed him to cross checkpoints without a search, an intelligence source told AFP.
At the end of June, 14 fighters from the Hezbollah Brigades, a PMF faction, were arrested for attacks on Americans.
Three days later, 13 were released on the decision of a PMF military judge.
Kadhemi over the weekend hosted Iranian commander Esmail Qaani, Soleimani's replacement, telling him that "no country" could interfere in Iraqi-US relations, a source close to the discussions told AFP.
The relationship between Baghdad and Tehran, meanwhile, must be "state-to-state and not via militias," the source quoted him as saying, adding that groups that "draw their strength from Iran" had bombed Iraqi targets and embezzled money.