US troops fired tear gas on Wednesday as Iran-backed militiamen and other protesters who had gathered outside the American embassy in Baghdad for a second day set fire to the roof of a reception area inside the embassy compound.
Dozens of Iran-allied militiamen and their supporters had camped out at the gates of the embassy overnight, a day after they broke into the compound, vandalising a reception area and smashing windows before pulling back.
It was one of the worst attacks on a US diplomatic mission in years.
The US Marines guarding the embassy fired tear gas on Wednesday as more crowds arrived and after the protesters lit a fire on the roof of the reception area. Smoke rose from the building.
There have been no reports of any injuries since the protests began.
The militiamen were protesting over deadly US air strikes which targeted an Iran-backed militia over the weekend, killing 25 fighters.
Those strikes were in response to a rocket attack on an Iraqi army base that killed a US contractor.
Iran and its allies have faced unprecedented mass protests in recent months and heavy US sanctions against Iran have hit its economy and raised tensions across the region.
In Iraq, the protesters have been angered at their own government’s corruption and economic mismanagement, as well as its close ties to Tehran.
US President Donald Trump blamed Iran for the attack on the embassy and Defence Secretary Mark Esper later announced the immediate deployment of an infantry battalion of about 750 soldiers from the army’s 82nd Airborne Division to the Middle East.
He did not specify their destination, but a US official familiar with the decision said they will go to Kuwait.
Iran has denied any involvement in the attack on the embassy.
Foreign Ministry spokesman Abbas Mousavi was quoted by state media on Tuesday as warning the US against any “miscalculation” in the worsening stand-off.
Iran’s supreme leader, Ayatollah Ali Khamenei, criticised the US air strikes on the Iran-backed Iraqi militia on Sunday.
In remarks carried by the semi-official ISNA news agency, he accused the US of taking revenge on Iran for the defeat of the Islamic State group, which he said was an American creation.
In an apparent reference to Mr Trump’s allegations of Iranian involvement, Ayatollah Khamenei said “if the Islamic Republic makes a decision to confront any country, it will do it directly”.
The US and Iran have vied for influence over Iraq since the 2003 US-led invasion that toppled Saddam Hussein.
Iran has close ties to Iraq’s Shiite majority and many of its major political factions, and its influence has steadily grown since then.
Iran helped to mobilise tens of thousands of mostly Shiite militiamen to battle the Islamic State group when it stormed across northern and western Iraq in 2014 as the armed forces collapsed.
In the subsequent campaign against the extremists, the US and Iran both provided vital aid to Iraqi forces, who eventually declared victory in December 2017.
The political influence of the Iran-backed militias, known as the Popular Mobilisation Forces, has risen in recent years, and their allies dominate the parliament and the government.
That has made them the target of mass protests since October that are unrelated to the attack on the embassy.
The anti-government protesters have attacked Iranian diplomatic missions and the local headquarters of parties affiliated with the militias across southern Iraq. They have also set up a major protest camp in central Baghdad.
For weeks, the anti-government protesters have been trying to enter the Green Zone housing the government and the US embassy, but have been beaten back by security forces, who have killed hundreds of demonstrators.
The militiamen and their supporters, however, were able to quickly enter the Green Zone and mass in front of the embassy, with little if any resistance from authorities.
By Wednesday morning, they had set up a small sit-in of their own, with around 50 tents erected between two main gates about 500 yards apart.
Demonstrators set up a makeshift clinic and cooks with aprons reading “Popular Mobilisation Forces logistical support” served meals out of giant pots. Mobile toilets were also set up in the area.
Vehicles belonging to the Popular Mobilisation Forces, with government plates, were parked nearby, and the militiamen manned checkpoints where they searched all those arriving at the site of the demonstration.
Outside one of the gates, a Shiite cleric recited verses from the Muslim holy book, the Koran, through a loudspeaker. Another cleric led the protesters in midday prayers.
Demonstrators could be seen hurling rocks over the walls of the embassy compound, where US troops responded by firing tear gas from the roofs of buildings.
Iraqi security forces deployed nearby watched the stand-off unfold without intervening.