The United States says its forces have killed Iran's most senior general, Qassem Soleimani, in an air strike on Baghdad airport.
Iran has confirmed the death of General Qassem Soleimani, who was the commander of the Islamic Revolutionary Guard Corps.
The Pentagon said President Donald Trump ordered the killing of General Soleimani, claiming he was "actively developing plans to attack American diplomats and service members in Iraq and throughout the region".
A statement read: "General Soleimani and his Quds Force were responsible for the deaths of hundreds of American and coalition service members and the wounding of thousands more.
"He had orchestrated attacks on coalition bases in Iraq over the last several months – including the attack on December 27th – culminating in the death and wounding of additional American and Iraqi personnel.
"General Soleimani also approved the attacks on the U.S. Embassy in Baghdad that took place this week."
The operation at Baghdad airport comes as hundreds more US marines are sent to Iraq, to reinforce security at the American embassy there - after days of violent protests over US air strikes on an Iranian-backed militia.
Last weekend, the US military carried out "precision defensive strikes" against Iranian-backed paramilitaries in Iraq and Syria.
Five facilities controlled by the Kata'ib Hezbollah group were successfully targeted, in response to repeated attacks on Iraqi military bases hosting US forces.
The Pentagon claim the strike "was aimed at deterring future Iranian attack plans", adding the US "will continue to take all necessary action" to protect its people and interests, echoing the statement released after Sunday's strikes.
Since the air strike, President Trump has published a single tweet of an American flag.
Iran has responded to the attack, President Hassan Rouhani warning of "harsh retaliation", labeling the General's death "martyrdom" and describing him as the "international face of resistance".
"All enemies should know that the jihad of resistance will continue with a doubled motivation, and a definite victory awaits the fighters in the holy war," said Mr Rouhani during a televised statement.
Three days of national mourning were also declared by Iran's leader.
US Defense Secretary Mark Esper said in a statement: "Let me speak directly to Iran and to our partners and allies. To Iran and its proxy militias: we will not accept continued attacks against our personnel and forces in the region.
"Attacks against us will be met with responses in the time, manner, and place of our choosing.
"We urge the Iranian regime to end their malign activities."
The Baghdad airport strike also killed Abu Mahdi al-Muhandis, deputy commander of Iran-backed militias in Iraq known as the Popular Mobilisation Forces, and five others, according to Iraqi officials.
US Secretary of State Mike Pompeo has taken to social media sharing what he claims to be a video of Iraqis "dancing in the street for freedom; thankful that General Soleimani is no more."
This move marks the latest escalation in tensions between Iran and the West, with some concern from US officials over the legal standing behind the attack.
US Democratic Senator Richard Blumenthal said Mr Trump owed a full explanation to Congress and the American people following the attack.
"The present authorisations for use of military force in no way cover starting a possible new war," he said.
"This step could bring the most consequential military confrontation in decades."
Though US leaders claim broad authority to act without congressional approval when American personnel or interests are facing an imminent threat, the Pentagon did not provide evidence to back up its assertion that General Soleimani was "actively planning" new attacks against Americans.
Cover image: General Qassem Soleimani in June 2018 (Picture: PA).