The Islamic Revolutionary Guard has confirmed it launched the attack targeting the Erbil and Al Asad bases in retaliation for last week’s killing of Major General Qassem Soleimani in a US airstrike just outside Baghdad airport.
US and Iraqi officials have said there are no immediate reports of casualties – and the Ministry of Defence has confirmed no UK personnel were affected.
Other coalition partners – Germany, Denmark, Norway, Italy, Finland and Poland – also said none of their troops were hurt.
Prime Minister Boris Johnson said the UK condemned the attack and warned Iran should not repeat “these reckless and dangerous attacks” – adding that Qassem Soleimani “had the blood of British troops on his hands”.
Iraqi officials said four of the 22 missiles failed to launch. Tehran had informed Iraqi Prime Minister Adil Abdul-Mahdi just after midnight on Wednesday that the “response to the assassination of the martyr Qassem Soleimani had begun or it will start in a little while”.
Mr Abdul-Mahdi said he was told the strike would be limited to where the US army is located in Iraq “without specifying its location”.
He said the Americans called him at the same time to say rockets were falling on Al Asad, Erbil “and in other locations”.
More than 5,000 US troops and 400 British soldiers remain in Iraq, along with other foreign forces, in a coalition that has trained and backed Iraqi forces against the threat of IS militants.
Sky’s Middle East correspondent Mark Stone, who is near Erbil, said two missiles fell short of the base and are lying unexploded in a village next to it as Kurdish forces guard the area before Iraqi or US forces manage to detonate them.
Moments after the attack, US President Donald Trump tweeted: “All is well! Missiles launched from Iran at two military bases located in Iraq. Assessment of casualties & damages taking place now.
“So far, so good! We have the most powerful and well equipped military anywhere in the world, by far! I will be making a statement tomorrow morning.”
Iranian president Hassan Rouhani vowed the missile attacks will not be the country’s final retaliation for Maj Gen Soleimani’s assassination, saying he will “kick all US forces out of the region”.
The attack is a major escalation between the US and Iran and is the Middle East country’s most direct assault on America since the 1979 seizing of the US embassy in Tehran.
It is also the first time in recent years Washington and Tehran have attacked each other directly instead of through proxies across the region.
Iranian state television described the ballistic missile attacks as the “first step” – with a Revolutionary Guard commander warning that Tehran will not spare American troops.
“[Donald Trump] should think about withdrawing troops from the region and not to leave them within our reach,” the statement said.
The US and its regional allies have also been warned not to retaliate.
A presenter on Iranian state TV has claimed – without offering evidence – that the strikes have killed “at least 80 terrorist US soldiers” and also damaged American helicopters, drones and other military equipment.
Sky’s Mark Stone said this should be “taken with a pinch of salt” as the Iraqi, US and British governments have all said they have not sustained any casualties.
Javad Zarif, Iran’s foreign minister tweeted: “Iran took & concluded proportionate measures in self-defense under Article 51 of the UN Charter targeting base from which cowardly armed attack against our citizens & senior officials were launched. We do not seek escalation or war, but will defend ourselves against any aggression.”
Iranian Supreme Leader Ayatollah Ali Khamenei called the missile strike a “slap in the face” of the Americans, adding that military retaliation is not sufficient.
“The corrupt presence of the US in the region should come to end,” he said.
After the strikes, a former Iranian nuclear negotiator posted a picture of the Islamic Republic’s flag on Twitter, appearing to mimic Mr Trump, who posted an American flag following the killing of Maj Gen Soleimani last Friday.
Sky’s foreign affairs editor, Deborah Haynes, says the risk of the US and Iran sliding into a direct war is more acute now than at any time in the last four decades.
A US government statement said: “It is clear that these missiles were launched from Iran and targeted at least two Iraqi military bases hosting US military and coalition personnel at Al Asad and Erbil.
“We are working on initial battle damage assessments.
“These bases have been on high alert due to indications that the Iranian regime planned to attack our forces and interests in the region.
“As we evaluate the situation and our response, we will take all necessary measures to protect and defend US personnel, partners, and allies in the region.”
Vladimir Dzhabarov, a politician in Russia’s upper house of parliament, warned: “Reciprocal strikes by the US and Iran may lead to an all-out war in the region. If Washington sees that it can’t achieve its goals, there’s a danger of a nuclear war.”
He also called for the UN Security Council to get involved to prevent further escalation in the Middle East.
Al Asad air base, in Iraq‘s western Anbar province, was first used by American forces after the 2003 US-led invasion that toppled dictator Saddam Hussein.
It later saw American troops stationed there amid the fight against the Islamic State group in Iraq and Syria.
Hours after the missile attack, a Ukraine International Airlines Boeing 737 carrying 176 people, including three British people, crashed shortly after take off from Iran’s main international airport on Wednesday morning.
There were no survivors and Ukraine’s president has ordered criminal proceedings to be opened.
Authors: Alix Culbertson and Connor Sephton