Image source, Reuters

Former President Donald Trump, who is the frontrunner to become the Republican nominee for the election later this year, said the attack "would never have happened if I was president".

It's worth a reminder that tensions between the US and Iran were high during Trump’s term as president - and US forces in Syria were attacked several times between 2016 and 2020, including one attack that killed four troops.

Trump’s rival in the contest to become the Republican presidential nominee, Nikki Haley, has encouraged Republican rally-goers to “lift up” the families of the casualties of the attack “in prayer”.

Senate Republican minority leader Mitch McConnell said: "The entire world now watches for signs that the president is finally prepared to exercise American strength to compel Iran to change its behaviour. Our enemies are emboldened."

And Senator Lindsey Graham said the Pentagon should respond by targeting Iran “not only as reprisal for the killing of our forces, but as deterrence against future aggression”.

This was also echoed by Tom Cotton, a Republican senator from Arkansas, who called for "devastating military retaliation" against Iran.

Violence has spread across the Middle Eastpublished at 08:26 Greenwich Mean Time 29 January

08:26 GMT 29 January

Hugo Bachega
Middle East correspondent, in Lebanon

It was almost inevitable that American troops would be killed. Since the start of Israel’s war against Hamas in Gaza, in response to the Hamas attacks in Israel on 7 October, US bases in Iraq and Syria have been attacked more than 150 times, according to US officials.

President Biden has accused “radical Iran-backed militant groups” in Syria and Iraq for the latest attack, which killed three US servicemen in a base near the Jordan-Syria border, and vowed to respond.

The attention is now on how this response is going to look like. So far, American forces have carried out limited retaliatory strikes in Iraq and Syria, which have been unable to stop the attacks.

This dramatic development shows how violence has spread across the Middle East amid the war in Gaza.

Image source, EPA

Apart from the attacks in Iraq and Syria, the Houthis in Yemen have targeted commercial vessels in the Red Sea and the Gulf of Aden, leading to retaliatory strikes by the US, the UK and other countries.

Here in Lebanon, Hezbollah has attacked positions in northern Israel almost every day. All these players are supported by Iran, part of it calls the "Axis of Resistance".

Iran said it was not involved in the attack in Jordan. President Biden, meanwhile, will face pressure to give a strong reaction, and some of his Republican critics are already calling for strikes in Iran itself.

"Hit Iran now. Hit them hard," Senator Lindsey Graham said. This is unlikely, as the White House has been trying to prevent a wider conflict in the region. A large military reaction, which could have unpredictable consequences, is something President Biden wants to avoid at all costs.

Iranian Foreign Ministry spokesperson Nasser Kanani this morning dismissed as "baseless" the US accusation about Iran's involvement in yesterday's drone attack on the US base in Jordan.

Kanani insisted that Iran was "not involved in the decision making of Resistance groups" in how they chose to "defend Palestinians or their own countries". Tehran refers to its networks of proxies and allied groups in the region as the "Axis of Resistance".

Joe Biden has said that the attack was carried out by "radical Iran-backed militant groups".

Earlier, a spokesperson of Iran's UN mission said Iran had "nothing to do with the attacks in question", adding "the conflict has been initiated by the US military against resistance groups in Iraq and Syria, and such operations are reciprocal between them".

Ultra-conservative daily newspaper Keyhan praised "the busy day of the Iraqi Resistance" with "eight attacks" on US and Israeli targets in "less than 24 hours".

Biden's response needs to be carefully chosenpublished at 08:07 Greenwich Mean Time 29 January

08:07 GMT 29 January

Gary O'Donoghue
Washington correspondent

The US has been able to contain its response to around 150 attacks on its bases in the Middle East since October simply because the strikes by Iranian-backed groups have led to not much more than minor injuries.

But the fact that three US service personnel have been killed this time means the response will have to be different - both because this is an election year and because public opinion will clamour for it.

Typically presidents ask for a menu of military options in these cases - which could range from hitting the group responsible, all the way to direct assaults on Iranian assets - something already demanded by one senior Republican senator.

The problem for Joe Biden is finding a path which is at once proportionate and avoids accusations of weakness - while avoiding a wider escalation - not an easy thing to achieve in the current circumstances.

Image source, Planet Labs/AP

Details are still emerging following the attack on the US base, but here is what we know so far:

• The attack targeted a US base in north-eastern Jordan, near the Syrian border, known at Tower 22
• It’s believed the drone struck living quarters in the base
• Three US troops were killed and at least 34 are being evaluated for possible traumatic brain injuries, US officials say
• The US is blaming Iran-backed military groups over the attack. Iran has denied any involvement

Image source, .

Image source, US CENTRAL COMMAND

The attack on a US base is the first drone attack that killed US troops, but this is not the first US military fatality amid escalating tensions in the region since Hamas's 7 October attack on Israel.

Two US Navy Seals who went missing during an operation to seize Iranian-made weapons - bound for Houthis in Yemen - were presumed dead, the US military said earlier this week.

The incident took place on 11 January when commandos were boarding a ship off the coast of Somalia.

According to media reports, one was swept away and the second jumped in to save him.

"We mourn the loss of our two Naval Special Warfare warriors, and we will forever honour their sacrifice and example," said the head of Central Command, Gen Michael Erik Kurilla.

The US Navy identified the two as 27-year-old Navy Special Warfare Operator 2nd Class Nathan Gage Ingram and 37-year-old Navy Special Warfare Operator 1st Class Christopher J Chambers.

Iran has an interest in making life uncomfortable for the USpublished at 07:41 Greenwich Mean Time 29 January

07:41 GMT 29 January

Paul Adams
Diplomatic correspondent

Ever since tensions erupted across the Middle East, in the wake of the Hamas attacks of 7 October and Israel’s offensive in response, Washington has been trying to prevent the conflict from spinning out of control.

Its forces across the Middle East have experienced scores of missile and drone attacks which, perhaps inevitably, have now resulted in the deaths of American servicemen.

How does Washington respond, in a way that doesn’t simply tip the region closer to a wider war?

For all the danger of this moment, which pits US forces against Iranian allies and proxies around the region, it’s still the case that neither America nor Iran is interested in seeing things get worse.

But as long as the war rages in Gaza, Iran has an interest in making life as uncomfortable as possible for Israel’s American backer. And that means that the risk of escalation is constant.

An escalation fraught with riskpublished at 07:37 Greenwich Mean Time 29 January

07:37 GMT 29 January

Lyse Doucet
Chief international correspondent

Image source, Getty Images

The death of three US service members, and injuring of many others, now ratchets up the pressure on the US commander-in-chief, President Joe Biden.

This sharp escalation seemed to have been all but inevitable.

Since mid-October, US military installations in Iraq and Syria have repeatedly come under attack by Iran-backed militias, injuring a growing number of US soldiers. The US has repeatedly retaliated by striking targets in both countries.

But this time, the US will need to consider whether to hold Iran itself responsible. It’s an option, and an escalation, fraught with significant risk.

The US knows it now needs to be seen to do more to protect the lives of its servicemen and women.

The president’s critics will exploit this crisis to accuse him again of being “soft on Iran”.

But his presidency has been about fighting faraway wars with clear red lines to avoid dragging Americans into a much costlier engagement.

Both Washington and Tehran, long locked in animosity, have carefully avoided direct confrontation in this current conflagration.

• Read more from Lyse Doucet here

Nadia Ragozhina
Live reporter

Good morning. We are restarting our coverage of the drone attack at a US base near the Syria-Jordan border that killed three American troops and injured dozens others.

Here is a quick recap of the latest lines:

• Iran has denied that it was behind the attack - its mission to the UN said "Iran had no connection and had nothing to do with the attack on the US base"

• The attack was on the Tower 22 airbase, US media reported, which is in Rukban, northeast Jordan
• It remains unclear who exactly is behind the attack. US Secretary of Defence Lloyd Austin blamed it on "Iran-backed militias" and US president Joe Biden vowed retaliation "at a time and place of our choosing"
• In addition to those killed, US officials said at least 34 others were injured. Eight were evacuated for medical treatment outside of the base, and some are in critical but stable condition
• Jordan has condemned the attack and said it continues to co-operate with the US to secure the border and to fight terrorism

Stay with us as we bring you all the latest lines and developments.