Saudi Arabia's terrified crown prince Mohammed bin Salman has been forced into hiding as Houthi rebels continue to hit Riyadh with deadly missile strikes.
The capital city's international airport was struck again on Sunday, killing one person and injuring 11 others.
The attack came just 24 hours after the deadliest strike on Saudi Arabia in a decade when a projectile hit King Khalid International Airport, killing 13 and injuring hundreds.
After this serious escalation in the war between the Saudi-led coalition government and Iran-backed Houthi fighters, Donald Trump warned the US could intervene.
Yesterday he waded in on the conflict, telling reporters he 'may' join a counter attack after the Saudis vowed to retaliate.
But a terrified crown prince has been driven into hiding as Houthi strikes on Riyadh intensify.
Mohammed bin Salman, 41, has for the past six days reportedly been moving between heavily guarded palaces with bunkers, according to officials.
The last time he was seen in public was on Tuesday, when he gave blood in a bid to support a national donation drive.
Saudi crown prince Mohammed bin Salman, 41, has been forced into hiding and is reportedly moving between heavily guarded palaces with bunkers as Houthi attacks on Riyadh intensify
Surveillance footage shows smoke and fire as people react at the moment of an attack at King Khalid International Airport in Riyadh
Houthi rebels claimed responsibility for the attack, which killed one person and injured 11 others
The Wall Street Journal reports: 'The 41-year-old crown prince is shuttling between heavily guarded palaces equipped with bunkers and is guarded by a handpicked security team, officials familiar with his movements said.'
Meanwhile schools across the capital have been forced to close and are operating with remote learning as Houthi attacks intensify.
It comes after President Trump hinted that Washington could intervene against the Houthi rebels as he continues to wage war on Iran.
Last month he described the crown prince as a 'good friend'.
When asked by reporters about the momentum that Houthi fighters were gaining in Yemen, he said: 'Everything is gonna work out fine and dandy. It's gonna be very good.'
And yesterday, when quizzed about US involvement in the conflict, the president said he is 'going to look at it'.
The Houthi strikes on Saudi Arabia on Sunday drew widespread criticism as the UK and EU condemned the attacks and reaffirmed their support for the country.
British Defence Secretary Wes Streeting said the Houthis' missile strikes were 'contemptible' and described them as 'dangerous escalation' in the war.
The UK has warned against travel to Saudi Arabia - advising British nationals to 'continue to avoid King Khalid International Airport in Riyadh until the airport is secure'
The attack on King Khalid International Airport in Riyadh on Saturday left 13 dead and more than 300 injured
A thick black column of smoke and flames could be seen rising from Riyadh airport
An urgent evacuation was triggered at the international travel hub as all flights to Riyadh had either been diverted or cancelled
He told Sky News: 'What we've seen overnight is a dangerous escalation and I'm afraid an increasing pattern of behaviour from the Houthis that's targeting civilian sites in Saudi Arabia.
'This is completely contemptible action and it's one of the reasons why the UK is providing support to Saudi Arabia in the form of air defences, but also air-to-air refuelling.
'We want to see an end to this conflict. It cannot be right that the Houthis are attacking civilian targets in this way.'
Meanwhile EU chief Ursula von der Leyen joined the chorus of condemnation as she too labelled the attacks a 'dangerous escalation' while calling on the Houthis to halt strikes on civilian targets.
She said: 'These attacks by Iran's proxies are pushing the region into a spiral of violence.
'They are destabilising crucial global transport and energy nodes with shockwaves sent through the world. These murderous attacks at civilians must stop at once.'
She added that the EU stands in 'solidarity with Saudi Arabia'.
The Houthis last night claimed responsibility for the attacks on King Khalid International Airport yesterday, which killed one person and injured 11 others.
The group said it had targeted the location several times as well as Saudi energy facilities, a day after Saturday's deadly attack.
Military spokesman Yahya Saree said the Iran-backed group 'carried out four qualitative operations in the past 24 hours using ballistic and cruise missiles and drones'.
Saudi Arabia's civil aviation authority condemned the 'heinous attack' – saying it resulted in 'material damage'.
The authority said: 'The attack resulted in the death of a Pakistani resident - may God have mercy on him - and the injury of 11 others.'
It came just hours after the rebel group warned that Saudi airports are 'potential targets and sites for operations by our forces'.
Mr Saree urged 'everyone to take our warnings seriously,' adding that Saudi Arabia 'bears responsibility' for failing to intercept its missiles.
On Saturday, 13 people were killed in a missile strike on the Riyadh airport while more than 300 were left injured.
Four Saudi citizens were among the dead, including a captain with the national airline as well as two Bangladeshis, one US citizen, one Egyptian, one Jordanian, one Syrian, one Palestinian, one Sudanese and one Indian.
The wreckage of the Saudia Airlines plane at King Khalid International Airport following an attack on Thursday
People gather outside a metro station on the road to King Khalid International Airport in Riyadh after the latest attack by Houthi rebels left 13 dead and more than 300 injured
Near the airport, passengers carrying luggage could be seen standing on the pavement at a metro station
The strike hit a passenger terminal at King Khalid on Saturday.
It was the deadliest on the kingdom in over a decade, when an Islamic State suicide bomber killed 21 worshippers in a Shia mosque in the eastern Qatif governorate.
US Secretary of State Marco Rubio condemned Saturday's incident and shared that one unidentified American died.
He said: 'The United States strongly condemns the recent attacks on the Kingdom of Saudi Arabia by the terrorists Houthis, including today's strike on King Khalid International Airport in Riyadh that took numerous innocent lives, including an American citizen.'
Mr Rubio continued: 'These reprehensible attacks demonstrate a blatant disregard for innocent civilian life. They must stop now.
'We stand with the Kingdom of Saudi Arabia and its people and extend our condolences to the victims and their families.'
Saudi coalition spokesman Major General Turki al-Malki described the strike as a 'cowardly terrorist attack' against a civilian facility.
The civil war in Yemen flared back to life in July after a four-year, UN-brokered truce collapsed, months into a wider Middle East war that has rocked the region and roiled energy supplies and markets.
Saudi Arabia leads an international coalition that has supported Yemen's government militarily since 2015 and is now being drawn deeper into its impoverished neighbour's conflict.
Mr Trump has said he will speak with Saudi crown prince Mohammed bin Salman, calling what happened in Saudi Arabia 'not acceptable'.
He told reporters: 'It's not good... I'm not happy.'
US media outlets have reported that previous Saudi requests for US military assistance in dealing with the Houthis have been rebuffed.
If Mr Trump does decide to get involved, it would likely escalate the ongoing war between the US and Iran.