A Shi'ite fighter, center, mans a heavy machine gun as he takes his position on at the outskirts of Balad, north of Baghdad December 25, 2014. (Stringer/Reuters)

Iranian military involvement has dramatically increased in Iraq over the past year as Tehran has delivered desperately needed aid to Baghdad in its fight against Islamic State militants, say U.S., Iraqi and Iranian sources. In the eyes of Obama administration officials, equally concerned about the rise of the brutal Islamist group, that’s an acceptable role — for now.

Yet as U.S. troops return to a limited mission in Iraq, American officials remain apprehensive about the potential for renewed friction with Iran, either directly or via Iranian-backed militias that once attacked U.S. personnel on a regular basis.

A senior Iranian cleric with close ties to Tehran’s leadership, who spoke on the condition of anonymity to discuss security matters, said that since the Islamic State’s capture of much of northern Iraq in June, Iran has sent more than 1,000 military advisers to Iraq, as well as elite units, and has conducted airstrikes and spent more than $1 billion on military aid.

“The areas that have been liberated from Daesh have been thanks to Iran’s advice, command, leaders and support,” the cleric said, using the Arabic acronym for the group.

At the same time, Iraq’s Shiite-led government is increasingly reliant on the powerful militias and a massive Shiite volunteer force, which together may now equal the size of Iraq’s security forces.

Although the Obama administration says it is not coordinating directly with Iran, the two nations’ arms-length alliance against the Islamic State is an uncomfortable reality. That’s not only because some of the militia shock troops who have proved effective in fighting the Islamic State battled U.S. forces during the 2003-2011 war there, but also because, in Syria, Iran continues to support President Bashar al-Assad, whom the United States would like to see toppled. U.S. diplomats, meanwhile, are pushing ahead with negotiations to reach a deal on Iran’s nuclear program to prevent the country from developing a nuclear weapon.

Ali Khedery, who advised several U.S. ambassadors in Iraq, said the tensions that fueled a U.S.-Iran confrontation in Iraq after 2003 are masked by the shared desire to defeat the Islamic State, also known as ISIS.

“ISIS will be defeated,” said Khedery, who runs a strategic consulting firm in Dubai. “The problem is that afterwards, there will still be a dozen militias, hardened by decades of battle experience, funded by Iraqi oil, and commanded or at least strongly influenced by [Iran’s Revolutionary Guard Corps]. And they will be the last ones standing.”

While the departure of U.S. troops in 2011 provided space for Iran to expand its influence in Iraq, Tehran’s support for paramilitary groups has intensified since the appearance of the Sunni militant group, which Iran’s Shiite leaders see as a serious threat to their interests. Combat troops from the Quds Force, a unit of the Revolutionary Guard Corps, now travel to Iraq “from time to time for specific operations with coordination with the Kurdish and Iraqi governments,” the senior Iranian cleric said.

Qassim Soleimani, the Quds Force commander, has become the face of Iran’s operations in Iraq, with photos of the commander on the front lines circulating on social media.

“He’s our friend, and we are very proud of his friendship,” said Hadi al-Amiri, who heads the Badr Brigade, a Shiite militia. “Anyone now who comes and helps us fight Daesh, we welcome them. We cannot liberate the country by the Iraqi forces alone.”

James Jeffrey, a former U.S. ambassador to Iraq, said the Obama administration may have made a mistake by not conducting limited airstrikes after the Islamic State’s initial advance.

Iraqi officials pleaded for assistance this summer as the militants appeared poised to overrun the Iraqi Kurdish city of Irbil and even Baghdad, the capital. But White House officials, frustrated by what they saw as the sectarian policies of then-Prime Minister Nouri al-Maliki, insisted first on political reforms.

“The Iraqis were in desperate straits, and the only ones who came to their rescue was Iran,” Jeffrey said. “These guys will remember that.”

During that time, Iraqi Kurds, the United States’ most constant ally in Iraq, accepted weapons from Iran. “If it was Iran that was coming to [our] aid or the United States, we needed to prevent Irbil from falling into the hands of ISIS,” said a Kurdish official, who, like other officials, spoke on the condition of anonymity to discuss security matters.

The collapse of much of Iraq’s army in June also provided momentum and popular support for the increasingly public operations of Iranian-backed militias, such as the Badr Brigade, Kataib Hezbollah, Asaib Ahl al-Haq, and a growing number of smaller splinter groups.

Sheik Jassim al-Saidi, a commander with Kataib Hezbollah, said his group has more than tripled in size since June, now boasting more than 30,000 combatants.

“Iran never left Iraq,” he said in an interview in a house next door to his Baghdad mosque, which has turned into a military base for militia fighters and is packed with crates of weapons. “This very close relationship has made Iran support Iraq all they can.”

Saidi flicked through pictures on his phone showing him visiting Iran’s Supreme Leader Ayatollah Ali Khamenei during a recent visit to Iran.

Kataib Hezbollah, designated a terrorist organization by the United States, has received new supplies of Ashtar and Karrar rockets from Iran in recent months, he said. The Karrar has been used by the group only once, Saidi said, against an American base in 2011. “It was like a thunderbolt falling from the sky on them,” he said.

American unease about the militia resurgence intensified when U.S. officials detected a lot of chatter via intelligence and diplomatic channels after Obama’s Sept.­­ 10 speech, in which he outlined his administration’s expanded strategy for countering the Islamic State, including airstrikes and a growing U.S. force in Iraq.

“There was a lot of commotion . . . a lot of Shiite militant mobilization in a way that made us very nervous,” a senior U.S. official said. U.S. diplomats worked for weeks to allay Iranian concerns about a U.S. return to Iraq, reaching out to Iraqi Shiite officials in order to telegraph a message to Tehran: Renewed U.S. military involvement in Iraq would be much more limited than it was last time.

“That message we do know resonated and got through to people all over, in Iran and elsewhere,” the official said.

As Obama deploys a force of up to 3,000 to retrain Iraqi troops, there have been no signs of hostility between U.S. forces and Iranian advisers or Shiite militiamen. Unlike in the past, U.S. troops will be confined to bases or headquarters and will not have direct combat roles.

Yet the possibility for confrontation is “something we’re constantly worried about . . . as we flow more personnel in there,” a senior U.S. defense official said.

Reports of abuses by Shiite militiamen have increased in recent months, raising fears that militia death squads that helped fuel past sectarian violence are on the march.

Another U.S. official said the militias’ combat power has come “at a steep price.”

“Various Shia militants have pursued scorched-earth tactics, leading to the displacement of thousands of Sunni civilians,” the official said.

American officials are also watching to see whether Iraqi Prime Minister Haider al-Abadi has the political clout to hold his unity government together and keep paramilitary forces in check.

Obama’s top advisers are betting that the United States can help contain militia power in the long term by rebuilding a smaller, stronger Iraqi army and backing a new national guard that might incorporate Sunni and Shiite paramilitary fighters.

“This is the single best opportunity we have to counter the Shia militant efforts and mitigate the influence that Iran will have,” the senior U.S. official said.


Morris reported from Baghdad.