Iran's supreme leader and Trump trade blame over US embassy siege in Baghdad as diplomats cower in safe room

Iran's supreme leader and US President Donald Trump are locked in an unprecedented war of words over the storming of the American embassy in Iraq, each blaming the other for unrest engulfing the country

Mr Trump ordered hundreds of US troops to the region after thousands of angry supporters of an Iranian-backed militia chanting "Death to America" besieged the mission on Tuesday, forcing staffers to take refuge in a safe room.

Ayatollah Ali Khamenei, Iran’s highest religious and spiritual authority, blamed the US for the recent unrest, warning the president that Tehran was not afraid to defend its interests.

US Marines guarding the mission fired tear gas on Wednesday as more crowds arrived and lit a fire on the roof of the reception area.

“Iran will be held fully responsible for lives lost, or damage incurred, at any of our facilities,” Mr Trump tweeted before his administration announced the immediate deployment of an infantry battalion of about 750 soldiers.

“They will pay a very BIG PRICE!,” he said. “This is not a Warning, it is a Threat. Happy New Year!”

Over the weekend, the US carried out strikes on positions of Iran-backed militia Khataeb Hizbollah in western Iraq in retaliation for rocket fire that killed an American civilian contractor at a military base in northern Iraq on Friday.

In another tweet, Mr Trump accused Tehran of "orchestrating" that day's storming of the US embassy in Baghdad by protesters angry over the American raid.

Khamenei, not known to have ever directly addressed Mr Trump on social media responded by saying the US was ultimately responsible.

“That guy has tweeted that we see Iran responsible for the events in Baghdad & we will respond to Iran,” he said, referring to Mr Trump. “1st: You can’t do anything. 2nd: If you were logical —which you’re not— you’d see that your crimes in Iraq, Afghanistan… have made nations hate you.

“If the Islamic Republic decides to challenge & fight, it will do so unequivocally,” he continued, quote-tweeting the US president. “We’re not after wars, but we strongly defend the Iranian nation’s interests, dignity, & glory.”

The two countries have been battling for influence in Iraq, which has tried since the fall of Saddam Huseein's government to balance ties between the foes.

The image of the biggest and most heavily fortified US embassy in the world, a symbol of America’s vast presence in Iraq, coming under attack signalled Washington’s weakened power in the region.

Dozens of Iran-allied militiamen and their supporters had camped out at the gates of the embassy in Baghdad overnight, a day after they broke into the compound, trashing a reception area and smashing windows in one of the worst attacks on a US diplomatic mission in years.

The Population Mobilisation Forces (PMU) umbrella group issued a statement asking crowds to leave the embassy, and protesters withdrew later in the day.

Kataib Hizbollah said that this was only the "first message to the US", and that the next step will be to expel US troops from the country.

“America is the Great Satan,” they chanted, and “Death to America” — echoing the chants of Iranian revolutionaries who held US diplomats hostage in Tehran in 1979.

The violence comes as Iran and its allies have faced unprecedented mass protests in recent months and after heavy US 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 supporters who stormed the embassy on Tuesday were not the same group of protesters who have been out on the streets for months in largely peaceful demonstrations.

It was unclear how many diplomats and embassy staffers were holed up inside the compound, but there is believed to be a permanent presence of around 300-350. Many had already left in recent days and weeks and the security situation deteriorated in Iraq.

The ambassador had been out of the country on holiday at the time.

Mark Esper, Defense Secretary, later announced the immediate deployment of an infantry battalion of about 750 soldiers from the Army's 82nd Airborne Division to the Middle East, in “an appropriate and precautionary action taken in response to increased threat levels against US personnel and facilities, such as we witnessed in Baghdad today.”

Mike Pompeo, US Secretary of State, told Fox News there were no plans to evacuate diplomats from Baghdad or to withdraw any of the 5,000 troops in the country.

“We’re going to make sure that we do everything we can to keep that facility safe and secure and have the resources to push back against anything that may confront us there,” he said.