Facebook has suspended more than 350 accounts and pages with about 1.4 million followers after it said people connected to the government of Saudi Arabia have run a network of fake accounts and pages to promote state propaganda and attack regional rivals.
The latest takedown is part of an ongoing effort to combat "coordinated inauthentic behaviour" on Facebook and the first such activity it has linked to the Saudi government.
Countries in the Middle East have increasingly turned to Facebook, Twitter and Google's YouTube to peddle covert political influence online.
Reuters news agency detailed an expansive Iran-backed campaign last year and Riyadh has been accused of using the same tactics to attack regional rival Qatar and spread disinformation following the murder of dissident journalist Jamal Khashoggi.
Saudi Arabia has repeatedly denied any involvement in Khashoggi's death and has not responded to previous allegations about its activity on social media.
Last month, in a series of articles, Al Jazeera examined the role of Twitter in the Middle East since the Arab Spring.
Research revealed that Twitter manipulation during the Gulf crisis showed a vast network of bots that tried to popularise certain hashtags, sent out fake news, and disseminated propaganda before and shortly after the start of the blockade.
Facebook announces takedowns of "inauthentic behaviour" multiple times a month, but statements that directly link such behaviour to a government are rare.
"For this operation, our investigators were able to confirm that the individuals behind this are associated with the government of Saudi Arabia," said Nathaniel Gleicher, Facebook's head of cybersecurity policy.
"Any time we have a link between an information operation and a government, that's significant and people should be aware."
Gleicher said the Saudi campaign operated on Facebook and its Instagram photo-sharing platform, primarily targeting countries in the Middle East and North Africa, including Qatar, the UAE, Egypt and Palestine.
The operation used fake accounts posing as those countries' citizens and pages designed to look like local news outlets.
More than $100,000 was spent on advertisements, Facebook said.
"They would typically post in Arabic about regional news and political issues. They would talk about things like Crown Prince Mohammed bin Salman [MBS] - his internal and economic social reform plan, the successes of the Saudi armed forces, particularly during the conflict in Yemen," said Gleicher.
Facebook also said on Thursday it had suspended a separate network of more than 350 accounts linked to marketing firms in Egypt and the UAE.
In that case, it did not directly link the activity to a government.
Social media companies are under increasing pressure to help stop illicit political influence online.
Facebook has publicly announced 11 takedowns of "inauthentic behaviour" stemming from 13 different countries so far this year.