BAGHDAD (BLOOMBERG, AP, AFP) - Qassem Soleimani, the feared Iranian general who through proxy militias extended his country's power across the Middle East, has been killed in a US air strike in Baghdad.
"At the direction of the president, the US military has taken decisive defensive action to protect US personnel abroad by killing" Soleimani, the Defence Department said in a statement on Friday (Jan 3).
"General Soleimani was actively developing plans to attack American diplomats and service members in Iraq and throughout the region."
The death of Gen Soleimani, who led the Revolutionary Guards' Quds force, heightened fears of an armed conflict between the United States and Iran that could easily pull in other countries.
Tensions have been building for months, complicated by widespread protests in Iraq and Iran.
President Donald Trump had no immediate comment but tweeted the image of an American flag.
Iran's Supreme Leader Ayatollah Ali Khamenei has warned that a "harsh retaliation is waiting" for the US after the air strike.
The Iranian state TV carried a statement by Mr Khamenei also calling Gen Soleimani "the international face of resistance."
Mr Khamenei declared three days of public mourning for the general's death.
An adviser to Iran's President Hassan Rouhani quickly warned President Trump of retaliation from Teheran.
"Trump through his gamble has dragged the US into the most dangerous situation in the region," Mr Hessameddin Ashena wrote on the social media app Telegram. "Whoever put his foot beyond the red line should be ready to face its consequences."
Iranian state television later in a commentary called Mr Trump's order to kill Gen Soleimani "the biggest miscalculation by the US" in the years since World War II. "The people of the region will no longer allow Americans to stay," the TV said.
US Secretary of State Mike Pompeo posted a video on Twitter on Friday, saying it showed Iraqis "dancing in the street" over the killing of Gen Soleimani.
"Iraqis - Iraqis - dancing in the street for freedom; thankful that General Soleimani is no more," Mr Pompeo wrote, alongside footage of scores of people running along a road waving what appeared to be Iraqi flags and other banners.
The attack occurred near Baghdad international airport. Details remained unclear, but one of the people said an Iraqi militia leader, Abu Mahdi al-Muhandis was also killed.
The Iranian regime will be under "strong pressure" to strike back, said Mr Paul Pillar, a former US Central Intelligence Agency officer and a non-resident senior fellow at Georgetown University in Washington.
"Many Iranians will regard this event the same way Americans would regard, say, the assassination of one of the best known and most admired US military leaders. The potential for escalation has suddenly gone up."
Gen Soleimani, a veteran of the Iran-Iraq war, was a household name in Iran where he is celebrated for helping to defeat the Islamic State in Iraq and Syria (ISIS) and countering US influence.
He had been sanctioned by the US since 2007 and last May, Washington designated the Revolutionary Guards Corp in its entirety a foreign terrorist organisation, the first time the label has been applied to an official state institution or a country's security forces.
Earlier in the evening, Iraqi security forces said in a statement that the airport had been struck by rockets.
The assault in Baghdad marked the latest in a series of violent episodes that have strained already hostile relations between Iran and the US that began last week when an American contractor was killed in a rocket attack on an Iraqi military base in Kirkuk.
That in turn prompted an attack on the US embassy in Baghdad.
Mr Trump had tweeted a warning of dire consequences for Iranian aggression, with a jaunty twist at the end: "They will pay a very BIG PRICE! This is not a Warning, it is a Threat. Happy New Year!"
The killing of such a prominent member of the Iranian hierarchy was unexpected.
The attack was praised by some in Washington, though misgivings were expressed as well.
Republican Senator Marco Rubio of Florida said in a tweet: "They are entirely to blame for bringing about the dangerous moment now before us."
But Senator Chris Murphy, a Connecticut Democrat, said on Twitter that the administration had acted without congressional approval, and asked whether the killing risked "setting off a potential massive regional war".
A congressional Republican said Gen Soleimani had been responsible for hundreds of American deaths in Iraq and elsewhere.
Another said that Iran should be worried about American retaliation rather than the other way around.
Outside the government, the reaction wavered between a sense of justification and apprehension over Gen Soleimani's killing.
"If it is true that he has been killed, any effort at negotiations between the US and Iran would be off the table," said founding director of the Centre for Global Policy in Washington Kamran Bokhari.
"This could get ugly," Mr Mark Dubowitz, the chief executive of the Washington-based Foundation for Defence of Democracies, said. "The regime in Iran is now facing their worst nightmare: A US president willing to escalate using all instruments of national power."
Earlier on Thursday, US Defence Secretary Mark Esper told reporters at the Pentagon that the American military was moving from responding to Iranian-backed attacks to anticipating them.
"There are some indications out there that they may be planning additional attacks. That's nothing new," Mr Esper said. "If that happens, then we will act and, by the way, if we get word of an attack of some kind of indication, we would take pre-emptive action as well to protect American forces, American lives. The game has changed."
The latest violence in Iraq occurred in the wake of the anti-government protests that led to the resignation of Prime Minister Adel Abdul-Mahdi.
Some 500 people have died in clashes between security forces and protesters since Oct 1, according to Iraq's independent High Commission for Human Rights. Iraqis, mostly from the Shiite majority population, are protesting against corruption, poor services, and Iran's sweeping influence in the country.