Hundreds of pro-Iran protesters surrounded the United States embassy in Baghdad on Tuesday to demand an end to US "intervention" in the country.

Raising flags of the powerful paramilitary group Hashd al-Shaabi (Popular Mobilisation Forces or PMF), the crowds chanted "down, down USA".

Tuesday's rally was completely distinct from the recent, months-long protest movement which has seen tens of thousands of Iraqis demonstrate against the political establishment.

Most at the US embassy were supporters of the Hashd Al-Shaabi. Dressed in army fatigues, they gathered around the heavily fortified embassy in the Green Zone, where government buildings and foreign embassies in Baghdad are based, arguing in favour of a state-backed militia.

Within hours, dozens had broken into the embassy compound after smashing a main door and setting fire to the reception area, according to witnesses.

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Protesters told Al Jazeera that they stormed the embassy in response to US air attacks over Kataib Hezbollah positions in Iraq and Syria.

At least 25 members of Kataib Hezbollah forces, which belongs to the PMF, were killed and 51 others were injured in the attacks on Sunday.

The US said it launched the air attacks in retaliation to a rocket attack on Friday near Kirkuk - a raid that killed an American civilian contractor, and that Washington blamed on Kataib Hezbollah.

"We are the Hashd and we are here to take revenge," said a protester in his 40s, who refused to give his name for security reasons.

"We [are] protesting here to condemn the US strikes on the Hashd," said Haydar, a protester in his 20s. "The Hashd are the ones who protected Iraq against terrorism."

The Iran-backed Shia paramilitary group was aligned with the Iraqi government in its battle against the ISIL (ISIS) group. It was formally incorporated into the Iraqi military in July 2019.

As the sun set on Baghdad, members of the crowd told Al Jazeera they would try to erect tents for the night and that they were prepared to launch an open-ended sit-in around the embassy until they saw action taken to "end US presence and intervention in the country".

"We call on the Iraqi parliament to take action against the US. We want the Americans out," said Haydar.

Ali, who described himself as a PMF supporter, said: "We came to mourn the people who died as a result of the US strikes in Qaim and to condemn the source [US] of all evil in Iraq since 2003.

"We are here because we are against US presence in Iraq and its targeting of the Hashd al-Shaabi and we won't leave until parliament and the government puts an end to that."

Distinct crowds

The escalation in the Iraqi capital comes on the heels of months-long anti-government protests that have gripped Baghdad and Iraq's south since early October, with demonstrators calling for basic services, employment opportunities and an end to corruption.

The protesters' calls quickly developed into demands for a complete overhaul of the political system, which they view as corrupt and sectarian.

At least 470 protesters have been killed and more than 20,000 others were injured in a crackdown on the movement.

Renad Mansour, director of the Iraq Initiative at Chatham House in London, said it was important to distinguish between the protest movement and the crowds that gathered in the Green Zone on Monday.

"Although the protesters in Tahrir Square are against US interference, they represent a generation of young, disenfranchised Iraqis that stand against the ruling elite, the militias and armed groups," said Mansour.

"On the other hand, the protesters outside the US embassy support the PMF and their allied forces.

"Rather than being anti-establishment, they support the Iraqi ruling elite."

Mansour said that the tensions around the US embassy in Baghdad might affect the protest movement across Iraq.

"The risk of this development is that it may divert focus from what are legitimate concerns ... to a focus on US intervention and demands for a withdrawal of American forces from Iraq."

'They don't represent us'

Meanwhile in Tahrir Square, the epicentre of the protest movement in Baghdad, protesters distanced themselves from the crowds near the US embassy in the Green Zone.

"Demonstrations at [the] US embassy are a natural response to the US strikes over Hashd positions in Iraq," 27-year-old Ali Khraybit told Al Jazeera.

"We, the protesters of Tahrir Square, condemn the strikes of course, whether it be Iran or the US who was responsible for them," said Khraybit. "But we are staying here in the hub of the peaceful protest movement.

"The crowds in the Green Zone do not represent us. We want peaceful change," he added.

Khraybit said he worried the escalation would lead to chaos in Baghdad.

"We all know the Hashd has weapons. If the security forces try to disperse the crowds, we might see a lot of blood," he said.

Noor al-Araji, a 30-year-old protester in Tahrir Square said: "The protesters in the Green Zone do not represent us. They belong to and represent the Shia parties that we want overhauled."

"We condemn the spilling [of] blood and we stand against foreign intervention in Iraq. These escalations are due to an ongoing conflict between Iran and the US and we want to stay out of it.

"The world doesn't realise that the people in the Green Zone are not the same as the protesters in Tahrir Square. We are peaceful and that's why we've stayed away from the Green Zone today."

Abdallah al-Salam contributed to this report from Baghdad