Iraqi protesters have started to withdraw from outside the US embassy in Baghdad, the Iraq’s INA state news agency reports, after a powerful Iraqi Shi’ite militia called on its supporters to leave.

The Hashd Shaabi militia said in a statement that the call for withdrawal comes out of respect for a request from the Iraqi government.

Dozens of protesters and Hashd Shaabi supporters camped overnight outside the gates of the embassy after thousands converged on Baghdad’s heavily fortified Green Zone on Tuesday to decry US strikes that killed at least 25 militiamen on the weekend.

On Tuesday, Iraq’s caretaker Prime Minister Adel Abdel-Mahdi called on the protesters to leave, threatening to inflict the “toughest penalty” on those who attack foreign embassies.

Earlier

US troops have fired tear gas to disperse pro-Iran protesters gathered outside the US Embassy compound in Baghdad for a second day.

Dozens of pro-Iranian militiamen and their supporters had camped out at the gates of the embassy in Baghdad where they stayed the night.

The previous day they had broken into the compound, trashing a reception area and smashing windows in one of the worst attacks on the embassy in recent memory.

The US Marines guarding the embassy fired tear gas after the protesters lit a fire on the roof of the reception area. Smoke rose from the building.

President Donald Trump earlier tweeted that Iran ‘will pay a very big price’ over violent protests at the US embassy in Iraq, as more US troops are sent to the region.

Mr Trump said Iran would be held “fully responsible” for the attack on the US embassy compound in Baghdad, but it was unclear whether that meant military retaliation.

“They will pay a very BIG PRICE! This is not a Warning, it is a Threat. Happy New Year!” Mr Trump tweeted in the afternoon.

….Iran will be held fully responsible for lives lost, or damage incurred, at any of our facilities. They will pay a very BIG PRICE! This is not a Warning, it is a Threat. Happy New Year!

— Donald J. Trump (@realDonaldTrump) December 31, 2019

Defence Secretary Mark Esper later announced that “in response to recent events” in Iraq, and at Mr Trump’s direction, he had authorised the immediate deployment of an infantry battalion of about 750 soldiers to the Middle East.

Mr Esper said additional soldiers are prepared to deploy over the next several days.

“This deployment is an appropriate and precautionary action taken in response to increased threat levels against US personnel and facilities, such as we witnessed in Baghdad today,” Mr Esper said in a written statement.

Tuesday’s breach of the embassy compound followed American airstrikes on Sunday that killed 25 fighters of an Iran-backed militia in Iraq, the Kataeb Hezbollah.

The US said those strikes were in retaliation for last week’s killing of an American contractor and the wounding of American and Iraqi troops in a rocket attack.

“Iran killed an American contractor, wounding many,” Mr Trump tweeted from his estate in Florida.

“We strongly responded, and always will. Now Iran is orchestrating an attack on the US Embassy in Iraq. They will be held fully responsible. In addition, we expect Iraq to use its forces to protect the Embassy, and so notified!”

Iran killed an American contractor, wounding many. We strongly responded, and always will. Now Iran is orchestrating an attack on the U.S. Embassy in Iraq. They will be held fully responsible. In addition, we expect Iraq to use its forces to protect the Embassy, and so notified!

— Donald J. Trump (@realDonaldTrump) December 31, 2019

Dozens of militiamen and their supporters smashed a main door to the embassy compound and set fire to a reception area, but they did not enter the main buildings.

By early evening Tuesday, the mob had retreated from the compound but set up several tents outside for a sit-in. Dozens of yellow flags belonging to Iran-backed Shiite militias were plastered along the embassy’s concrete wall along with anti-US graffiti. American Apache helicopters flew overhead and dropped flares over the area in what the US military called a “show of force.”

Iran has denied it was behind the protests in Iraq and warned against any retaliation.

The 750 soldiers deploying immediately are in addition to 14,000 US troops who have deployed to the Gulf region since May in response to concerns about Iranian aggression, including its alleged sabotage of commercial shipping in the Persian Gulf.

The US also was sending 100 or more additional Marines to the embassy compound to support its defences.