Riyadh: Online armies of self-styled Saudi patriots riding a wave of state-led nationalism attack critics and what they call "traitors" of the kingdom -- but their growing clout has left the government uneasy.
Their rise has coincided with the ascent of Crown Prince Mohammed bin Salman, who has overseen Saudi Arabia's shift from austere religion towards hyper-nationalism as he pursues an ambitious transformation of the petro-state.
Trolls distorting political discourse are common in many countries, but Saudi Arabia's so-called cyber "flies" -- feisty defenders of state policy who often choose pictures of Saudi rulers as their avatar image -- are an increasingly powerful force.
Their posts frequently tag Saudi security agencies, and their collective roar often leads to detentions, sackings and harassment.
These "phantom accounts" were long thought to be linked to the government, arising as part of a policy driven by former royal court advisor Saud al-Qahtani.
Qahtani, sacked over the October 2018 murder of journalist Jamal Khashoggi, earned nicknames such as "Mr Hashtag" and "lord of the flies" for managing an electronic army to defend the kingdom.
But a rare debate on state television in June sought to distance them from the government.
"How dangerous are these accounts that use pictures of state symbols and deploy threats as if they are supported by the government?" asked a host on Ekhbariya television.
"They give the impression that they are a parallel government or even stronger than the government," replied Saudi academic Salih al-Asimi.
These accounts "gave themselves the right" to dig up dirt on those displaying insufficient patriotism, including excavating their old tweets as ammunition to attack them, Asimi said.
The debate, echoed by other pro-government media, was widely seen as a warning to nationalists to fall in line.
"These phantom accounts have proved to be valuable to Saudi Arabia's leadership," Annas Shaker, a Washington-based Saudi expert, told AFP.
"But as they become ever more powerful, the government wants to assert control and show that they are the ultimate authority."
However, the fact that Asimi himself got attacked online after the debate underscores the challenge of reining them in.
"What do they want us to do -- stop defending the nation?" one nationalist fumed on Twitter.
Many others, including a royal prince, sprang to their defence, using the hashtag "nationalist accounts are the nation's shield".
The accounts, which gained prominence in parallel with official crackdowns to smother dissent, evoke widespread fear.
Shaker recounted how they went after Huda al-Humood, a Saudi woman hired to lead an education ministry program in 2017, in a rare appointment.
They combed her Twitter account to dig up old posts they said were in favour of Qatar -- a rival of the kingdom -- and the banned Muslim Brotherhood. The witch hunt extended to her husband's account.
The campaign seemed to work, Shaker said. Within days of her appointment, Humood was sacked.
Many Saudi liberals have shut down their Twitter accounts, including those engaged in constructive criticism of Prince Mohammed's reforms.
Those who have not, tread with caution.
Before government job interviews, many say they scrub past references that could make them appear unpatriotic. In another extreme, it has encouraged fake displays of nationalism.
"Every day on Twitter I hurl an insult or two at Qatar," one government worker told AFP.
"I don't care about Qatar, but this way no one can accuse me of being unpatriotic if I speak out against other state policies."
Saudi Arabia, which accounts for the highest number of Twitter users in the Arab world, has faced accusations of trying to manipulate content on the platform.
Two former Twitter employees were charged last year with spying for the Saudi government.
Twitter has suspended hundreds of local accounts, some "linked to Saudi Arabia's state-run media apparatus" and engaged in coordinated efforts to "amplify messaging beneficial to the government".
The kingdom's sovereign wealth fund recently acquired a stake in Facebook, which last year said it dismantled a series of Saudi-linked propaganda accounts.
But while disabling computer bot activity may be easy, it will be harder to tame genuine accounts that experts say rose organically.
"Saudi views the online mobs as difficult to control," said Shaker.
"They attack foreign critics one day, senior government figures the next."
Their loyalty to the state could be further tested as Saudi Arabia enters a period of acute austerity, with the government chipping away at once-generous subsidies and handouts amid low crude prices.
"Nationalist sentiment advanced by the state may have created a Trojan Horse," said Eman Alhussein, a non-resident fellow at the Arab Gulf States Institute in Washington.
"These accounts... could become a challenge for the state."