IRAN has vowed “harsh retaliation” for a US airstrike near Baghdad’s airport that killed Iran’s top general Qassem Soleimani, the head of the country’s elite Quds Force.

The killing marks a major escalation in the standoff between Washington and Iran, which has veered from one crisis to another since President Donald Trump withdrew from the 2015 nuclear deal and imposed crippling sanctions.

Maryam Rajavi, President-elect of the National Council of Resistance of Iran (NCRI), described the “elimination” of Soleimani as an “irreparable blow to the clerical regime”.

“While the prospects for the ruling theocracy’s overthrow is within reach, it is time for the regime’s armed forces to refrain from firing on the Iranian people, lay down their weapons and surrender,” said Rajavi.

READ MORE: Elite Iranian commander Qassem Soleimani dies in US airstrike

“The armed forces’ patriotic personnel must join the people of Iran.”

The US has urged its citizens to leave Iraq “immediately” and the US State Department said the embassy in Baghdad, which was attacked by Iran-backed militia and other protesters earlier this week, is closed with all consular services suspended.

The National: Commander of Iran’s Quds force, General Qassem Soleimani

More than 5000 American troops are based in Iraq, where they mainly train Iraqi forces and help to combat militants of Daesh. Yesterday, the US announced it was sending nearly 3000 more to the Middle East to secure the situation. Officials said the troops are from the 82nd Airborne Division at Fort Bragg, North Carolina.

Iran’s Supreme Leader Ayatollah Ali Khamenei warned that a “harsh retaliation is waiting” for the US following the airstrike, calling Soleimani the “international face of resistance”. He declared three days of public mourning for the general’s death.

Iran also summoned the Swiss charges d’affaires, who represents US interests in Tehran, to protest about the killing.

Soleimani’s death, and any forceful retaliation by Iran, could ignite a conflict that engulfs the whole region, endangering US troops in Iraq, Syria and beyond.

Over the last two decades Soleimani had assembled a network of powerful and heavily armed allies stretching all the way to southern Lebanon, on Israel’s doorstep.

The US Defence Department said it killed him because he “was actively developing plans to attack American diplomats and service members in Iraq and throughout the region”. It also accused Soleimani of approving the orchestrated violent protests at the US embassy in Baghdad earlier this week.

Iranian state television called Trump’s order to kill Soleimani “the biggest miscalculation by the US” since the Second World War. “The people of the region will no longer allow Americans to stay,” it said.

The airport strike also killed Abu Mahdi al-Muhandis, deputy commander of Iran-backed militias in Iraq known as the Popular Mobilisation Forces (PMF), and five others, including the PMF’s airport protocol officer Mohammed Reda, Iraqi officials said.

Soleimani was the target of yesterday’s US attack, which was conducted by an armed American drone, said a US official.

His vehicle was his on an access road near Baghdad airport.

A senior Iraqi security official said the airstrike happened near the cargo area after Soleimani left his plane and joined al-Muhandis and others in a car.

The National: Donald Trump

Democratic presidential candidate Joe Biden said Trump had “tossed a stick of dynamite into a tinderbox”, and like other Democratic White House hopefuls criticised the president’s order, saying it could leave the US “on the brink of a major conflict across the Middle East”.

Global powers warned that the world has become a more dangerous place after Trump ordered the killing, and urged restraint on all sides.

China, Russia and France, all permanent members of the UN Security Council, took a dim view of the US airstrike.

In France, deputy foreign affairs minister Amelie de Montchalin said: “We are waking up in a more dangerous world. Military escalation is always dangerous. When such actions, such operations, take place, we see that escalation is under way.”

European Council president, Charles Michel, urged all parties involved to avoid further escalation, adding that the risk of the recent cycle of violence “is a generalised flare-up of violence in the whole region”.

Following the announcement of the air strike, US stocks fell, with the Dow Jones Industrial Average trading 172 points lower following a brief 360-point drop on opening. False reports of an attack on a US military base caused stocks to drop again yesterday evening. 

US crude oil futures went up 3.2% causing concern over a possible shock to the global economy.