Following the surrounding of the US Embassy in Baghdad by protesters on Tuesday, US Central Command buttressed the embassy by sending 100 US Marines and several AH-64 Apache attack helicopters to patrol the Iraqi capital.

“The Department of Defense is working closely with the Department of State to ensure the security of our Embassy and personnel in Baghdad,” US Secretary of Defense Mark Esper said in a Tuesday press release. “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."

The 100 Marines came from Kuwait and are part of the Special Purpose Marine Air-Ground Task Forces Crisis Response - Central Command, Marine Corps Times reported. Their deployment was preceded by approval from Iraqi Security Forces, the outlet noted.

VIDEO: AH-64 Apaches protect @USEmbBaghdad. 🚁“We have taken appropriate force protection actions to ensure the safety of American citizens...and to ensure our right of self-defense. We are sending additional forces to support our personnel at the Embassy.”~@EsperDoD 🇺🇸🇮🇶 pic.twitter.com/amABHBAOcL — OIR Spokesman Col. Myles B. Caggins III (@OIRSpox) December 31, 2019

​Video posted on Twitter by Col. Myles B. Caggins III, spokesperson for Operation Inherent Resolve, the US mission to destroy Daesh in Iraq and Syria, showed a pair of Apache attack helicopters soaring over the Tigris River, firing off flares designed to confuse heat-seeking missiles, but which have the side-effect of looking very intimidating. They also bear a superficial resemblance to white phosphorus munitions, which are so viciously deadly against personnel that their use is banned in urban areas.

The Marine unit’s Twitter account also posted photos of and the Marines preparing to head into Iraq on board an MV-22 Osprey tilt-rotor aircraft.

USMC reinforcements from Kuwait, Special Purpose Marine Air-Ground Task Force-Crisis Response-Central Command (SPMAGTF-CR-CC) 19.2, arriving via MV-22 Osprey in Baghdad pic.twitter.com/4Q4sWWPmcl — The Fulda Gap (@TheFuldaGap) December 31, 2019

​​The trouble started earlier on Tuesday when a large group of protesters gathered outside the US Embassy in Baghdad, angry over a series of US airstrikes against the Iraqi Shiite militia Kata'ib Hezbollah that killed 25 militia members and left 51 other people injured the previous day. Washington has claimed the group is backed by Iran and that the airstrikes were in response to an attack on the US base in Kirkuk, Iraq.

The US State Department confirmed the building itself was never breached by the protesters, but there were attempts to set fire to the embassy. Secretary of State Mike Pompeo also accused Iran of being behind the embassy siege.

Iran’s Foreign Ministry denied the US accusations on Tuesday, with ministry spokesperson Seyyed Abbas Mousavi saying Tehran "rejected accusations by American officials" calling them "empty" and warning the White House against further accusations.

The move has been condemned by Iraqi President Barham Salih and Iraqi Prime Minister Adel Abdul-Mahdi, who described the strikes as “unacceptable” and “harmful,” noting the existing agreement with Washington precludes unilateral action by coalition forces inside Iraq.

“We consider it a violation of Iraqi sovereignty and a dangerous escalation that threatens the security of Iraq and the region,” an Iraqi military spokesperson said, Sputnik reported.