At least 100 infantry Marines from a crisis response unit designed to respond to emergencies at U.S. embassies have been dispatched to Iraq, where supporters of an Iran-backed militia smashed into an American diplomatic facility on Tuesday.

The Marines are assigned to Special Purpose Marine Air-Ground Task Force-Crisis Response-Central Command, a ground-based unit spread across the Middle East, U.S. officials confirmed to Military.com. Video footage taken near the embassy shows some of the Marines arriving in Baghdad by helicopter.

The California-based 2nd Battalion, 7th Marines, is the infantry unit currently assigned to the crisis response task force. The unit -- one of several the Marine Corps created following the deadly 2012 attack on a U.S. post in Benghazi, Libya -- not only includes ground forces, but also air and logistics capabilities.

The Marines are trained and equipped to respond to a host of crises in the region, including security emergencies at U.S. embassies.

Related: US Fed Up with Baghdad's Failure to Act Against Iran-Backed Militias, State Officials Say

The grunts were sent in response to a mob breaching the embassy in Baghdad. The group broke down a door and set fire to the embassy's reception room in apparent retaliation for U.S. airstrikes carried out this weekend.

As people tried to scale the embassy walls, reporters said they were shouting "Death to America" and "Down, down USA!"

The breach was met with tear gas and sounds of gunfire, The Associated Press reported Tuesday.

U.S. Army Apache helicopters later flew over the embassy, dropping flares in a show of force, a U.S. official said. The official spoke on the condition of anonymity, citing ongoing developments on the ground.

Defense Secretary Mark Esper said Tuesday that Pentagon leaders are working closely with the State Department to ensure the security of personnel at the embassy.

"We have taken appropriate force protection actions to ensure the safety of American citizens, military personnel and diplomats in country, and to ensure our right of self-defense," he said in a statement. "We are sending additional forces to support our personnel at the Embassy."

Esper then called on the Iraqi government to "fulfill its international responsibilities" to protect U.S. personnel at the embassy.

Tensions have been high in the region, where the U.S. launched airstrikes Sunday on five Iranian-backed militia positions in Iraq and Syria. The strikes followed a series of rocket attacks on U.S. bases in Iraq from the Iranian-backed Kata'ib Hezbollah militia.

One of those attacks killed a U.S. contractor and wounded four American troops.

Pentagon spokesman Jonathan Hoffman said the strikes were intended to degrade the group's ability to carry out future attacks on U.S. and coalition troops. But Iraqi leaders have called the strikes, which killed dozens of members of the militia, a violation of that country's sovereignty.

The Marine Corps crisis response unit that's helping shore up security at the U.S. embassy includes about 2,000 more Marines.

"As of now, the situation remains fluid" at the embassy, the largest U.S. diplomatic facility worldwide in a highly restricted section of Baghdad known as the "Green Zone," but "everyone is safe," said a U.S. official, speaking on background.

There were no immediate reports of injuries to any U.S. personnel and all are accounted for, the official said. There also were no evacuations of U.S. personnel and no reports of demonstrations or incidents at other bases throughout Iraq, where about 5,000 U.S. troops are based, the official said.

Videos of the protests showed the use of tear gas and possibly stun grenades against the protesters, but the official said that U.S. personnel did not fire any shots or use crowd control munitions. The tear gas and stun grenades likely came from the Iraqi security forces.

The official also disputed Iranian news outlet reports that U.S. Ambassador Matthew Tueller and other personnel were evacuated from the Baghdad embassy at the height of the protests. Tueller was out of the country on vacation, the official said.

The embassy in Baghdad and the Green Zone have periodically come under threat since the U.S. invasion in 2003. In 2016, Marine reinforcements were sent to the embassy following violence in which protesters stormed the Iraqi parliament building.

The demonstrations Tuesday, in which protesters threw gasoline bombs, came after funerals in Baghdad for members of the Iranian-backed Kata'ib Hezbollah militia who were killed in U.S. airstrikes Sunday. Demonstrators then marched on the embassy from the funerals.

The airstrikes were approved by President Donald Trump following at least 11 rocket attacks in the last two months on U.S. facilities in Iraq, including the embassy and the Green Zone, State Department officials said Monday in a background briefing to reporters.

The latest attack last Friday on a U.S. base near north-central Kirkuk killed an American contractor and injured four U.S. troops, prompting Trump to give the go-ahead for the airstrikes.

Iraqi caretaker Prime Minister Adel Abdul-Mahdi spoke by phone with Esper on Sunday before the airstrikes were launched to warn of "dangerous consequences" if they were carried out, according to Iraq news outlets.

Hoffman said the airstrikes were "defensive" in nature and would serve as a warning to Iran to rein in the Shiite Iraqi militias under its control.

Pompeo spoke to Abdul-Mahdi and Iraqi President Barham Salih separately Tuesday by phone and "made clear the United States will protect and defend its people, who are there to support a sovereign and independent Iraq," State Department spokeswoman Morgan Ortagus said.

From his Mar-a-Lago estate in Florida, where he was on vacation, Trump sent out a tweet blaming the embassy demonstrations on Iran and calling on Iraq to protect U.S. personnel and property.

"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!" he wrote.

In a statement, Iran's Islamic Revolutionary Guard Corps said the Iraqi people and the Kata'ib Hezbollah militia had the right to "take revenge for and respond to the recent big crime committed by the Americans" in the airstrikes Sunday, according to Iran's Tasnim news agency.

Only the expulsion of "American occupier terrorists" will bring peace to Iraq, the IRGC statement said.

On Twitter, former National Security Adviser John Bolton, whose testimony has been sought in the impeachment proceedings against Trump, blamed the attack on the U.S. Embassy in Baghdad on Iran, and said the incident should not be seen as an indicator of growing Iraqi opposition to the U.S. presence.

"It's a sign of Iranian control over Shia militia groups, not a sign of Iraqi anti-Americanism. We must protect our citizens from Iranian belligerence," Bolton said.

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-- Gina Harkins can be reached at gina.harkins@military.com. Follow her on Twitter @ginaaharkins.

-- Richard Sisk can be reached at richard.sisk@military.com.

Read more: Iran-Backed Iraqi Militia, Mob Breach US Embassy Compound