Flying low over the Jordanian desert, F-16 fighter jets flatten targets in the sand while tanks unleash their deadly firepower and paratroopers dot the late afternoon sky.
These were the scenes a fortnight ago in Operation Eager Lion, the United States-led exercise involving 8,000 service personnel that the military insists was only routine.
In Jordan, though, the war games now feel like a precursor to the invasion of neighbouring Syria. And not just because live rounds were fired.
Concerns were raised further last week with news that the CIA and US Special Forces are training Syrian rebels at a secret base in the remote south-west of the country.
The Free Syrian Army fighters are mainly from Daraa, where the uprising began in March 2011.
It is not known how many of the rebels have passed through the US base, but it is understood 20 to 45 at a time have been attending two-week courses since December – and are being trained with Russian-designed 14.5mm anti-tank rifles and 23mm anti-aircraft weapons.
Operation Eager Lion may have ended two weeks ago but 900 combat-ready American servicemen remain behind, with many now based close to the strategically important northern border.
Disquiet over what may happen next is felt all over this desert kingdom – a key ally of Britain and America and one that has played a pivotal role in the power struggle in the Middle East.
Few Jordanians doubt that the West is now more determined than ever to meet the rebels’ demand for heavy arms.
But while they share the same desire to rid Syria of President Bashar Assad, the majority – motivated by a strong sense of self-preservation – view the unfolding scenario as potentially disastrous.
And not just because of the fear that the weapons will find their way into the hands of extremist elements among the rebels, including Al Qaeda-linked Jabhat al-Nusra.
Or that Assad’s friends in Russia and Iran will respond in kind.
this because they believe the arms will inevitably have to pass through Jordan to reach Syria. This, they argue, will enrage Assad, who may well seek revenge.
In the wood-panelled bars of Jabal Al-Weibdeh, the Christian quarter of the capital Amman, opinion-formers and decision-makers meet daily over tea and shisha to discuss the threat to their country.
Here, whenever David Cameron and Barack Obama speak of civil war in Syria, which has already cost the lives of more than 100,000 men, women and children, their words are seized upon, scrutinised and debated.
Coverage of the G8 summit in Northern Ireland was almost as keenly watched in Amman as the Arab Idol song contest.
Should Jordan be seen to be too readily helping its Western allies, it is argued, Assad might activate Syrian ‘sleeper cells’ in the capital and elsewhere.
‘It is estimated that around 4,000 Assad loyalists and Hezbollah members have infiltrated our towns and cities and are ready and waiting to rise up,’ said Ahmad Hassan Alzoubi, one of Jordan’s foremost political commentators.
Their numbers have been swollen by fighters who have entered the country among the waves of Syrian refugees.
Mr Alzoubi added: ‘The fear is they will try to destabilise our country.’ Targets are thought to include strategic military facilities.
A senior government official said that the cells ‘may try to assassinate prominent Jordanians’.
In the past, sleeper cells in Jordan have been activated by Hezbollah for attacks on Israel through the West Bank.
Even so, Jordan remains, at least for now, one of the region’s safest countries, its significance arising partly from its strategic location at the crossroads of the Holy Land.
It is also one of only two Arab nations to have made peace with Israel.
‘So far the spotlight has been on northern Syria, around Aleppo, where the rebels are strong,’ said Mr Alzoubi.
‘But the significance of what is happening in the south, near our border – which is near Damascus – cannot be overlooked.
‘This is the route the West will use to move arms for the rebels. And, ultimately, it is only in the capital of Syria that victory for the rebels can be achieved.’
For the time being at least Jordan’s Prime Minister Abdullah Ensour insists that US forces are not preparing for a war in Syria.
He said they are in the Arab kingdom to bolster its defence and prevent the civil war from spreading across its border.
Of the 900, he added, 200 are training Jordanians to handle a chemical attack. The remaining 700 are manning a Patriot missile-defence system and F-16 fighter jets.
‘If the war continues, it’s a problem, and if it ends with the collapse of the regime, we also have a problem,’ said Mr Ensour.
He added that the fall of Assad’s regime would leave a ‘vacuum, whereby attacks and conflicts would persist’. That scenario appears to be a long way off.
For now, few believe Assad will go anywhere soon, particularly as he appears to be in the ascendancy.
After successfully recapturing the town of Qusair near the Lebanese border, regime forces have moved on rebel strongholds around Damascus and the Jordanian border.
‘The regime is directing its forces to the border region,’ said Abu Mohammad al-Darawi, who heads a Free Syrian Army battalion outside the southern city of Daraa.
‘We can no longer guarantee the safety of refugees trying to enter Jordan.’
Yesterday, thousands of refugees were stranded across the border because pro-Assad forces, fighting alongside mercenaries from Hezbollah, the Lebanese Shia party, had cut off access routes to Jordan, which has already taken in more than 550,000 people.
More than 160,000 of them are in the Zaatari refugee camp, which has effectively become Jordan’s fifth largest city. While many are still desperate to reach it, others are already starting to leave.
Already this month some 9,000 Syrians abandoned Zaatari to answer the rebels’ call to return to their homeland and ‘defend’ their towns.
Many more have simply had enough of the camp, which has become increasingly lawless, and long to start a new life in Amman which is off-limits to them.
Bearing the brunt of the Syrians’ frustrations have been humanitarian agency workers. ‘There have been around 70 cases where agency workers have been attacked with sticks and rocks,’ said Mohammed Ali, a clinic manager with Jordan Health Aid Society.
‘Last month a policeman was stabbed by a refugee. There have been demonstrations, with refugees burning down their tents. People are becoming frustrated because they have been here so long.’
On the surface, however, the camp appears well-equipped, with schools, sports facilities, shops and even a tailor. ‘I don’t want to go back to fight in Syria – I just want to go home and live peacefully,’ said Abu Jarah, a 30-year-old barber.
He arrived at Zaatari in December with his wife after his two-year-old daughter, Shouq, was shot dead by regime forces as he carried her across a street in Daraa.
‘The bullet hit her in the head and she was blown out of my arms,’ he said. ‘It was the most terrible day of my life.’
On Wednesday Jordan’s King Abdullah said: ‘We will not allow anything to compromise our national security or harm our citizens.’
On Friday, at Jordan’s main border crossing with Syria, a burly guard’s discourse on Manchester United’s chances of success without Sir Alex Ferguson was brought to an abrupt halt by a burst of mortar fire.
The loud boom broke the desert stillness and made the guard spring from his chair. Jabbing the air with a cigarette, he estimated that it came from at least two miles away, which seemed to calm his colleagues.
Eventually their tension subsided, but didn’t disappear entirely. The men fell silent, their discussion about football and ‘Mr Alex’ forgotten.
Despite the King’s assurance, his people remain edgy. They simply can’t escape the feeling that Jordan, a bit-part player, has been reluctantly shoved on to centre stage.