We now have a little more from General Douglas Sims, who says the US is "pretty confident" that the locations it struck were "pretty significant in degrading capability".

As we've been reporting, the US launched strikes on 85 targets across seven locations - four in Syria and three in Iraq.

B1 bombers, which show lethal power across intercontinental range, were used in Friday's retaliation. The full-scale impact is yet to be assessed.

"We will know better in terms of what [the bomb damage assessment] looks like tomorrow," Gen Sims adds.

Image source, Reuters

National Security Council spokesman John Kirby says the strikes are “just the first set of responses”.

Kirby has been giving more details in a phone call with reporters, which we are listening in to.

"There's been no communications with Iran since the attack that killed our three soldiers in Jordan," he says - referring to the attack by an Iran-backed militia group on Sunday.

Kirby says the targets hit today were selected to avoid civilian casualties and “based on clear irrefutable evidence that they were connected to attacks on US personnel in the region”.

He wouldn’t comment on any timings or locations of future operations.

Jonathan Beale
Defence correspondent

US officials say they believe the strikes were successful – but they are still assessing the damage.

They said seven locations were hit – four in Syria and three in Iraq.

At those seven locations there were 85 individual targets – including groups associated with and supported by Iran’s Revolutionary Guard Corps.

The US has repeated that it is not seeking a conflict with Iran itself. Officials say the strikes tonight were aimed at degrading military capabilities and to put an end to attacks on US bases in the region.

They said all US aircraft involved in tonight’s strikes were now out of harm's way.

The US used 125 munitions over a period of just over 30 minutes.

A senior US official added “this will not end tonight”.

US General Douglas Sims has just been briefing reporters about the retaliatory strikes in Iraq and Syria.

Sims said cloudy weather had made it difficult to launch a strike in the past few days, but that all changed today.

He adds that they're "very confident in the targets that we struck today".

Bernd Debusmann Jr
Reporting from Washington DC

Several military experts have told me that by delaying the strike, the US risked diminishing their impact and not creating the desired deterrent on Iran-backed militias operating in the region.

"The [approach] raises the question of whether this will restore any deterrence, if it ever existed," said Brian Katulis, a senior fellow at the Middle East Institute who previously worked with the National Security Council.

"It potentially takes the force out of what they're trying to do, if in fact they are trying to restore deterrence and keep American troops in the region safe."

Another expert, Arabian Gulf States Institute of Washington fellow Hussein Ibish, said the delay appeared to be the US signalling "what they're not going to do, which is strike inside Iran".

"If they did strike in Iran, the Republican standard bearers like Donald Trump would denounce Biden for being a warmonger," he said. "It's a political trap. Everybody gets that, so they're not going to fall into that trap."

Appearing on the BBC channel, Robin Wright, a foreign policy analyst, highlighted that these strikes happened near to where American soldiers are stationed.

She explained Biden had to examine when and how to strike, but had to calculate how to protect Americans in the area.

There are "a lot of pieces in motion", she said.

As she appeared on air, criticisms from across the political aisle began to trickle in.

One US congressman, Byron Daniels, wrote online that "these strikes should have occurred the same day our servicemembers were killed".

When asked for her response to that, Wright said because it is an election year, there is nothing that a current administration could do that would not face criticism.

Iraqi official says if you know you are a target, 'you simply disappear'published at 22:54 Greenwich Mean Time 2 February

22:54 GMT 2 February

Hugo Bachega
BBC Middle East correspondent

For days, American officials had been telegraphing that retaliatory strikes would come, after Sunday’s deadly attack on a base in Jordan.

This marks an escalation of the violence in the Middle East, although US authorities insist they do not want to trigger a wider war in the region.

American officials have suggested the US response will be carried out over several days and hit Iranian personnel and interests in Iraq and Syria, where the first strikes have been conducted.

As expected, infrastructure and weapons were the initial targets. With the element of surprise gone, top leaders would have certainly left their positions, which could have been part of the US strategy to limit casualties and, as a result, reduce tensions.

“If you know you’re a target, you simply disappear,” an Iraqi official told me. It is not clear how – or if – Iran or the groups it supports will respond.

Apart from the militias in Iraq and Syria, Iran also supports the Houthis in Yemen, who have targeted commercial vessels in the Rea Sea and the Gulf of Aden, and Lebanon’s Hezbollah, which has attacked positions in Israel almost every day.

They are part of what Iran calls Axis of Resistance.

Iranian officials have given indications that they do not want a direct confrontation with the US, something that would be catastrophic for the country and an existential threat to the regime in Tehran.

Image source, Shutterstock

Let's bring you a statement now from the US Secretary of Defense, Lloyd Austin.

Following the attacks that killed three American soldiers, the US military forces "conducted strikes on seven facilities, which included more than 85 targets in Iraq and Syria", he said.

Austin said the targeted sites were ones that Iran’s Islamic Revolutionary Guard Corps (IRGC) and affiliated militias used to attack US forces.

He added that President Biden has ordered additional actions to "hold the IRGC and affiliated militias accountable for their attacks on US and Coalition Forces".

"I will not tolerate attacks on American forces," he concluded. "We will take all necessary actions to defend the United States, our forces, and our interests."

US attacks on Iranian-backed targets were carefully calibratedpublished at 22:36 Greenwich Mean Time 2 February

22:36 GMT 2 February

Paul Adams
Diplomatic correspondent

These strikes fall roughly in the middle of the range of actions predicted by analysts after US forces came under attack in Jordan last weekend.

As expected, the US hit a mixture of Iraqi and Syrian militia groups, plus their Iranian backers, the Islamic Revolutionary Guards Corps (IRGC) Quds Force.

This was a carefully calibrated set of attacks.

The broad range of targets (85 in all) and quantity of weaponry used (125 precision munitions) represents a bigger response than anything the US has done in Iraq and Syria since 7 October, but a smaller one than some critics of the Biden administration were urging.

There were no strikes on Iranian soil and an Iranian warship in the Red Sea, thought to be involved in helping direct Houthi attacks on commercial shipping, was not targeted.

The White House wanted to make an emphatic statement – a warning to Iran and its allies that the deaths of US service personnel will not go unanswered – but did not want to trigger an automatic Iranian response.

We don’t know the extent of the damage or casualties caused by America’s action, but by telegraphing its intentions over several days, Washington may have deliberately given Iran and its allies a chance to get personnel out of harm’s way.

In some ways, this could mirror Iran’s response to the 2020 US assassination of the IRGC general Qasem Soleimani.

Five days after the assassination, Iran fired volleys of missiles at US bases in Syria. But only after giving the US several hours’ notice.

Image source, EPA

US President Joe Biden has just released a statement on the retaliatory attacks.

"This afternoon, at my direction, US military forces struck targets at facilities in Iraq and Syria that the IRGC and affiliated militia use to attack US forces,” he said.

He added that he had earlier attended the "dignified return of these brave Americans" and spoke with their families.

"Our response began today. It will continue at times and places of our choosing."

Biden said the US "does not seek conflict in the Middle East or anywhere else in the world" but gave a warning.

"Let all those who might seek to do us harm know this: If you harm an American, we will respond."

Will retaliatory strikes result in deterrence - or escalation?published at 22:16 Greenwich Mean Time 2 February

22:16 GMT 2 February

Tom Bateman
BBC State Department correspondent

The US statement, external contains a detailed list of targets in Iraq and Syria hit by a weight of American airpower - more than 125 munitions, some flown in long-range bombers from the US.

There is specific mention of targeting the Quds Force, the elite unit of Iran’s Islamic Revolutionary Guards. That’s significant, and consistent with some of the threats American officials had made in the run up to tonight’s strikes.

Many of the other sites hit, says the US, are control centres, weapons and storage facilities. Syrian state media says the US “aggression” has led to casualties and injuries.

The Pentagon is attempting to show forceful retaliation. Iran has already said this week it would respond “decisively” to any attack on its interests or nationals.

The coming hours or days will determine whether President Biden’s attempt to calibrate the strikes - by avoiding Iranian soil but going after Iranian personal - have deterred Iran’s allies, or have escalated the conflict.

Image source, AFP

The Quds Force is the international arm of Iran's Islamic Revolutionary Guards Corps (IRGC), which Tehran is said to use to further its foreign policy goals.

Iran has acknowledged the role of the Quds Force in the conflicts in Syria, where it has advised forces loyal to President Bashar al-Assad and armed thousands of Shia Muslim militiamen fighting alongside them, and Iraq, where it has backed a Shia-dominated paramilitary force that helped defeat the Islamic State.

The group has also been accused by the US of plotting or carrying out terrorist attacks, directly or through its proxies, in five out of seven continents.

General Qasem Soleimani - the Force's infamous commander - was killed in a US airstrike in Baghdad, Iraq, in January 2020.

Read more about the Quds Force and the IRGC here.

On Thursday, Reuters reported that Iran was pulling some of its top commanders from Syria after a spate of deadly Israeli attacks - in a bid to avoid being directly drawn into a wider conflict in the region.

Reuters cited unnamed sources, saying the Iranian commanders had left along with dozens of mid-ranking officers.

As our security correspondent points out, neither Iran or the US want to get into a full-scale war and both have said so.

And according to CNN on Thursday, US officials say there are signs the Iranian government is becoming increasingly concerned about the actions of its proxy groups in the region, who have launched over 160 attacks on US forces since October.

But Iran has said it will respond decisively to any attack on its territory, its interests, or Iranian nationals outside its borders.

We have some confirmed details now from the US Central Command (CENTCOM).

They say American forces launched airstrikes in Iraq and Syria against Iran’s Islamic Revolutionary Guards Corps (IRGC) Quds Force and affiliated militia groups at 16:00 EST (21:00 GMT).

• More than 85 targets were hit.
• Numerous aircraft, including long-range bombers flown from the United States, were involved.
• More than 125 precision munitions were used.

Targets included command and control operations, centres, intelligence centres, rockets, and missiles, and drone storage sites, and logistics and munition supply chain facilities of militia groups.

As we’ve been reporting, the US has launched strikes in Syria and Iraq.

It’s in response to an attack in north-eastern Jordan on Sunday by militants backed by Iran. Iran has denied involvement.

But why is the US targeting these places?

Well there are a large number of bases, weapons stores and training depots across Iraq and Syria belonging to the myriad of Iran-backed militias.

These militias are trained, equipped and funded by Iran's Revolutionary Guards Corps (IRGC) Quds Force, but not necessarily directed by them.

These militias have launched more than 170 attacks on US bases in the region since 7 October. The US knows who they are and where they are.

And the US had already carried out missile strikes on some of these bases after separate attacks on US troops.

As we’ve just reported, the US has started to attack targets in Iraq and Syria.

It is the beginning of the US retaliation to a drone strike on a US military base in Jordan on Sunday by Iran-backed militants.

US soldiers in the region have been repeatedly targeted in Iraq and Syria by Iran's proxies since the outbreak of the Israel-Gaza conflict last October - but it’s the first time US soldiers have been killed by strikes in the region in that time period.

US intelligence believes that the drone used to attack the facility was manufactured by Iran, according to four US officials who have spoken to Reuters.

The three soldiers killed were members of the Army Reserve: William Rivers, 46, and Kennedy Sanders and Breonna Moffett, who were both in their 20s.

At least 41 others were wounded. We’ve been waiting to see how the US would respond, after the White House vowed it would do everything necessary to protect troops.

It emphasised, however, that it was not seeking a war with Iran.

The US has started air strikes against Iranian-backed groups in Syria and Iraq, two US officials told CBS News. They follow a drone attack that targeted a US military base in Jordan, which killed three American soldiers and injured dozens more.

More to come.