Iran-backed militiamen behind an attack on the U.S. embassy in Baghdad, Iraq, have begun retreating from the area on Wednesday following a threat from President Donald Trump to hold Tehran accountable for the siege.

“Supporters of the Kataib Hezbollah militia who had spent the night camped outside the embassy began dismantling their tents and leaving the area, saying they had won a victory and would now seek the withdrawal of U.S. troops from Iraq through the nation’s parliament,” the Washington Post reports.

The development comes after Department of Defense Secretary Mark Esper announced on Tuesday evening the deployment of 750 U.S. soldiers to the region in response to the attack. Esper said additional troops are prepared to ship out for reenforcement if needed.

Earlier Tuesday, President Donald Trump blamed Iran for orchestrating the attack and threatened the country will pay a “very big price.”

“The U.S. Embassy in Iraq is, & has been for hours, SAFE! Many of our great Warfighters, together with the most lethal military equipment in the world, was immediately rushed to the site. Thank you to the President & Prime Minister of Iraq for their rapid response upon request,” the president tweeted.

….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

“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!” he added.

The U.S. Marines guarding the embassy fired tear gas 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 deadly U.S. airstrikes that 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 U.S. contractor.

The violence comes as Iran and its allies have faced unprecedented mass protests in recent months and after heavy U.S. sanctions on Iran that have cratered 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.

The Associated Press contributed to this report.