Iranian-backed militia swarmed the U.S. embassy in Baghdad on Tuesday chanting “Death to America,” sparking widespread concern among officials in Iraq and Washington about further targeting of American outposts in the days to come.  

The protest escalated Tuesday afternoon in Iraq as individuals holding the flags of Kataib Hezbollah, which launched rocket attacks that killed an American contractor on Friday only to be hit by U.S. airstrikes on Sunday, scrawled graffiti on the walls of the compound and used long concrete poles to try and break through the doors and windows. 

Others climbed on top of one of the American buildings, hoisting the Kataib Hezbollah flags to the roof. The crowds eventually dispersed, but U.S. officials said they would send additional troops to the area to protect embassy staffers. The State Department said there were no plans to evacuate the compound.

The embassy protest took place after the U.S. launched a strike on Kataib Hezbollah in Iraq and Syria on Sunday, killing 24 people and wounding 50, according to a press statement from Kataib Hezbollah. Two days before that, the U.S. said the group launched rockets at a base near Kirkuk, Iraq, killing one American contractor. 

“We responded defensively to the Iranian proxy attack that killed an American citizen and wounded American and Iraqi soldiers,” Secretary of State Mike Pompeo said Tuesday. “Now, Iranian backed groups are threatening our embassy in Baghdad.”

The rocket strike in Kirkuk represented the culmination of tensions between the U.S.-led anti-ISIS coalition and Iranian-backed militias in Iraq that have been mounting as the Trump administration’s “maximum pressure” campaign against Iran intensified and the U.S.-Iran relationship veered towards aggressive confrontation.

After a series of attacks on Japanese, European, and Saudi oil tankers in the Gulf attributed to Iran in May, Secretary of State Mike Pompeo ordered the evacuation of non-essential personnel from the U.S. embassy in Iraq and its consulate in Basra, citing intelligence showing an increased risk to U.S. officials from Iranian-backed proxies in Iraq. 

Trump’s reckless decisions to walk away from the Iran [nuclear] Deal and now to launch airstrikes in Iraq without Iraqi government consent have brought us closer to war and endangered U.S. troops and diplomats.

Sen. Elizabeth Warren (D-MA)

The move, according to the Pentagon’s Lead Inspector General of Operation Inherent Resolve, established to fight the so-called Islamic State in Iraq and Syria, has affected all operations of Mission Iraq, limiting the mission’s ability to help Iraq become “a more resilient, independent, democratic country, and to support counter-ISIS efforts.”

The U.S. military footprint in Iraq also has shrunk due to growing tensions with Iran and the militias it supports. For more than a year Iraqi politicians have called on the United States to withdraw all of its troops from the country, saying their continued presence would make an already volatile situation all the more perilous.

Over the summer, a series of unexplained explosions at Iranian-backed militias’ ammunition storage facilities led to allegations that Israel had targeted Iranian ballistic missiles stored at the facilities. U.S. officials denied any involvement in the explosions, but Iraqi officials facing an onslaught of conspiracy theories and Iranian-backed militia outrage, restricted the the anti-ISIS coalition’s use of Iraqi airspace—a move that “hurt the Coalition’s ability to counter the ISIS threat in Iraq,” according to the most recent Pentagon report.

The swarm attacking the U.S. embassy on Tuesday alarmed Democratic lawmakers on Capitol Hill, concerned that the Trump administration’s maximum pressure policy had sparked an irreversible escalation with Tehran that could kickstart, at a minimum, a stand-off with Iranian-backed militias in Iraq. 

“Trump’s reckless decisions to walk away from the Iran [nuclear] Deal and now to launch airstrikes in Iraq without Iraqi government consent have brought us closer to war and endangered U.S. troops and diplomats,” Sen. Elizabeth Warren (D-MA), a Democratic presidential candidate, said on Twitter. “We should end the forever wars, not start new ones.”

Republicans took to social media to denounce the media’s use of the term “protesters” to describe the mass of people who encircled the U.S. embassy Tuesday, saying those who participated were directly linked to the Iranian-backed militias. 

Sen. Marco Rubio (R-FL) said the protesters were members of the Hezbollah militia operating in Iraq. “There’s zero question,” Rubio declared on Twitter. Photos surfaced on social media Tuesday showing leaders of Kataib Hezbollah at least mingling with the protesters at the American embassy.

No more Benghazis.

Sen. Lindsey Graham (R-SC)

Both the Senate and House foreign affairs committees called for briefings on the situation from top State Department officials. Meanwhile, Sen. Lindsey Graham (R-SC), a member of the Senate Armed Forces Committee, announced Tuesday on Twitter that he had met President Donald Trump in Florida to discuss the situation in Iraq, saying the president was “determined to protect American personnel” and that he expected “Iraqi partners to step up to the plate.” 

“No more Benghazis,” said Graham.

Not everyone believes that the flareup over Iranian-backed militias will mark the beginning of the end for the U.S. military presence in Iraq. “We both still realize we need each other and I don’t think this will serve as a break. It is a low point; I don’t think it’s a breaking point,” one former senior military officer told The Daily Beast.

“Iraq is in between two nation states, both of whom they need help from, both of whom they want good relationships with, and both of whom are at each other’s throats. Not to be too sympathetic to the Iraqi government, but they are in a very precarious position politically and they don’t have the depth or breadth of experience to work their way through it,” he said.

While it’s unclear yet whether Iraq will apply further restrictions on the U.S.-led anti-ISIS coalition in the wake of the U.S. strikes, experts say the impact of either a withdrawal or expulsion of U.S. forces would be clear.

“The effectiveness of the CT [counter terrorism] effort would be rapidly degraded by a U.S. pullout, and ISIS would likely begin to rebuild some higher-end attack capabilities, particularly car bomb and suicide bomber networks,” Alex Mello, a security consultant, told The Daily Beast.

The impact would likely be felt hardest among Iraq’s Counterterrorism Service (CTS) and other elite special operations units which U.S. special operators have spent years training and have fought alongside when the ISIS caliphate still stood. 

But Mello says conventional troops among Iraqi Security Forces would also feel the effect of a U.S. drawdown. “They’ve become accustomed to operating with U.S. support, particularly relying on airborne intelligence, surveillance and reconnaissance coverage during clearance operations. If U.S. combat air support was also withdrawn, ISIS would be able again to mass openly in large groups and potentially threaten to overrun Iraqi forward operating bases and larger combat outposts.”