Saudi Arabia fights pull of Islamic State
Just outside Riyadh, the dunes fill up at weekends with pleasure seekers, staking out picnic spots safe from the four-wheel drive vehicles that churn up sand as they race through the desert.
Mishan al-Onzi is hanging out with a group of his teenage friends. They are from the north of the country next to Iraq, where Islamic State (IS) controls large swathes of territory.
Mishan tells me that a friend from home has gone to Syria to join IS.
"Those from a lower class, who don't have any awareness, those are the people Daesh looks for," he says, using an Arabic acronym for the group.
"They are easy for Daesh to brainwash."
According to the Ministry of Interior, some 2,600 Saudis have joined extremist groups in Syria since 2011, around 600 of whom have returned. Last year alone, 400 were arrested in relation to IS activities inside the Kingdom.
It is a relatively low number, says Interior Ministry spokesman General Mansour Sultan al-Turki, but still a matter of deep concern.
"Whoever made [IS] made it for purposes and one of those purposes is really to attack Saudi Arabia," he says.
"They know that our borders are very well-protected so their idea is to do their best through propaganda, like inspire young Saudis to carry out any terrorist act on their behalf."
Saudi Arabia has invested heavily in its counter-terrorism forces since a wave of attacks by al-Qaeda militants in the mid-2000s.
But until recently it stood accused of empowering Islamist militants in nearby Syria, by permitting funding from sympathetic sheikhs, and backing Sunni Muslim groups in a proxy war with Shia Iran.
Then IS began to seize territory across Syria and Iraq and declared itself an Islamic Caliphate.
It has now vowed to take over Saudi Arabia, the birthplace of Islam and site of its holiest mosques.
Last year Riyadh made it a crime to join IS. And it mobilised Saudi clerics, who now condemn the group as un-Islamic.
But that has not included any soul-searching of their own ultraconservative creed, one that advocates harsh Islamic punishments which have been taken to extremes by IS.
The recent sentencing of Saudi blogger Raif Badawi to 1,000 lashes for insulting Islam prompted Western comparisons between the ideologies of Saudi Arabia and Islamic State.
"This is the basic problem we have with media like yourselves in mixing apples and oranges," countered the former intelligence chief Prince Turki al Faisal.
"Fahash is a terrorist group, it has no legal system," he said, using an Arabic word for obscene that rhymes with Daesh.
"The kingdom is a state, it has a judicial system that traces its history even longer than English common law."
The Saudis argue that they are trying to reform those who join extremist groups.
They gave me rare, but tightly controlled, access to a high security prison said to be holding IS inmates.
I was shown spotless corridors with doors painted a soothing lavender, a state-of-the art hospital, a bookstore, rooms for conjugal visits, even a human rights complaint box, an effort, apparently, to push back against accusations of torture.
The prisoners were kept out of sight though, apart from the one selected to speak to me.
Forty-five-year-old Manna Nasser told me he had gone to Syria to do relief work.
He chose the city of Raqqa as his base, he said, because at the time it was a refuge for those displaced by the conflict. But then it became IS headquarters.
"They threatened they would kill me if I didn't disown the Saudi royal family and the Arab leaders," he said.
"I was forced to pledge loyalty to them and follow their doctrine."
The tour continued at a government rehabilitation centre, a massive complex that brings in social workers, preachers, artists and psychologists in a holistic attempt to reintegrate extremists into society.
One man who had been through the programme told me he had tried to travel to Syria to fight jihad with Islamic State, but his ideas about holy war have since changed.
"I hear that [IS] is now fighting non-Muslims and Muslims," he said. "Thank God the centre lighted the way of truth for us".
But Saudi Arabia's puritanical version of Islam does share a strain of religious intolerance that IS has used to justify its killings of Shia and non-Muslims, says Jane Kinninmont, a London-based Middle East analyst.
"The tendency to declare other Muslims as 'kafir' or non-Muslim, that's something you see advocated by some officially sanctioned and tolerated Muslim clerics in Saudi Arabia," she says.
The message is important because in this socially conservative country, young people live on the internet, which makes them vulnerable to IS recruitment via social media.
And although Saudi youth are commonly perceived as pampered by the country's oil wealth, the state struggles to find jobs for all its young people, who make up more than two-thirds of the population.
Anecdotally, we heard of young men with no work or education who talked of escaping their bleak lives by joining Islamic State.
Getting to the battlefield is increasingly difficult, and the Saudis have also fortified themselves from outside attack.
The Kingdom's frontline with IS, its northern border with Iraq, is demarcated with a double fence that undulates across a vast windswept desert, monitored by high-tech surveillance cameras.
Members of Islamic State did clash with a border patrol early this year, killing three guards. But the threat is more internal than external.
And the Saudis are not questioning whether their ideology is in any way to blame.