Pro-Iran protesters dig in outside US embassy in Baghdad

Thousands of Iraqi supporters of the largely Iranian-trained Hashed al-Shaabi paramilitary force had gathered at the embassy on Tuesday, outraged by US strikes that killed 25 Hashed fighters over the weekend.

They marched unimpeded through the checkpoints of the usually high-security Green Zone to the embassy gates, where they broke through a reception area, chanting "Death to America" and scribbling pro-Iran graffiti on the walls.

The protesters set up portable toilets and some 50 tents outside the perimeter wall vowing not to leave until US forces quit Iraq.

On Wednesday morning, a truck delivered hundreds of mattresses in an indication of the protesters' plans.

Crowds of men, some in military fatigues, brandished Hashed flags and chanted anti-US slogans.

"I spent the night here and I won't leave until the Americans leave and we enter the embassy," said one protester, who identified himself only as Abbas.

Some protesters set US flags on fire and hurled rocks towards the compound.

Security personnel inside responded with tear gas, wounding several protesters.

'They will pay'

Tuesday's embassy attack was the latest episode in spiralling tensions between the United States and Iran since Washington abandoned a landamrk nuclear deal with Tehran in 2018.

Many of those tensions have played out in Iraq, which has close ties with both governments.

US forces, who number some 5,200 across Iraq, have faced a spate of rocket attacks in recent months which US officials have blamed on pro-Iran factions within the Hashed.

Last week, one of those attacks killed a US contractor, prompting retaliatory US air strikes on a hardline Hashed faction known as Kataeb Hezbollah (Hezbollah Brigades).

The strikes killed 25 fighters from Kataeb Hezbollah, which organised Tuesday's march to the embassy gates.

In his first comments on the strikes, Iran's supreme leader Ayatollah Ali Khamenei on Wednesday strongly condemned US "malice".

President Donald Trump and other top US officials have blamed Iran for the storming of the embassy compound.

"They will pay a very BIG PRICE! This is not a Warning, it is a Threat," Trump wrote on Twitter, adding "Happy New Year!"

Alarmed that protesters were able to reach the embassy so easily, US officials have pressured Iraqi forces to step up security and sent a rapid response team of marines to help guard the compound overnight.

US Defence Secretary Mark Esper said around 750 troops from the 82nd Airborne Division were prepared to deploy to the region in the coming days.

Ties 'coldest' in years?

By Wednesday, Iraqi forces had reimposed normal security measures around the perimeter of the Green Zone, usually inaccessible without a badge.

But they did not remove the crowds that had spent the night inside.

No US personnel were injured and US officials said there were no plans to evacuate the mission.

Ambassador Matthew Tueller, who had been on holiday, was said to be on his way back to Baghdad.

The attack highlighted the strains in the US-Iraqi relationship, which officials from both countries have described to AFP as the "coldest" in years.

The US led the 2003 invasion against then-dictator Saddam Hussein and has worked closely with Iraqi officials since then, but its influence has waned in the face of Tehran's growing clout in Baghdad.

The dramatic scenes at the embassy on Tuesday sparked comparisons with both the 1979 hostage crisis at the US embassy in Tehran and the deadly 2012 attack on the US consulate in Libya's second city Benghazi.

ak-sbh/mjg/kir