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LONDON — As the coronavirus pandemic brought death and misery across the US, a group of Iran-linked Twitter and Instagram accounts aggressively pushed for California to secede from the United States.

Marc Owen Jones, a professor of Middle Eastern studies in Doha, Qatar, analyzed thousands of posts and found evidence of coordinated activity that he says is intended to sow discord and unrest in the US at a perceived time of weakness.

Jones analyzed some 16,000 tweets, including replies and retweets, from more than 8,000 accounts using the hashtag #calexit, mostly on April 6 and 7.

Based on his analysis, he told BuzzFeed News there is strong evidence of inauthentic activity, including that 8% of the accounts sending the tweets were created in early April. Meanwhile, 10% of the accounts were created in January — it may seem like a lifetime ago now, but at the start of 2020 it looked like tensions between the US and Iran could escalate into full-blown conflict, after a US airstrike killed Qassem Soleimani, Iran’s country’s most powerful military leader at the time.

Jones said he believes the reason for the campaign is the same as many state-sponsored disinformation campaigns active since November 2016 — to sow discord among Americans. Russia has been accused of trying to interfere in Catalonia’s independence referendum and Brexit, although UK intelligence agencies found no evidence that Russia had influenced the outcome of the referendum.

On April 6, Marcus Ruiz Evans, the president of Yes California, posted a “message to the Islamic Republic of Iran” on YouTube, saying a future independent California would have a foreign policy distinct from that of the US.

The accounts Jones tracked on Twitter and Instagram did not specifically mention the coronavirus, but he said the subtext was clear.

“Any campaign like this seeks to exploit existing political tensions,” he said. “When there’s an opportunity or a perception that a society is vulnerable to polarization, then these campaigns will exploit that.”

“Coronavirus is a hugely political instrument,” he added. “It’s been instrumentalized by all sides, all political colors.”

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Asked how the platform is addressing disinformation campaigns, a Twitter spokesperson told BuzzFeed News the company “proactively monitors Twitter to identify attempts at platform manipulation and mitigate them.”

“If we identify campaigns on our service that we can reliably attribute to state-backed activity, either domestic or foreign-led, we will disclose them,” the spokesperson said.

Supporters of Californian independence — or Calexit in social media shorthand — argue that the state is one of the world’s largest economies and has a variety of domestic and foreign policy interests distinct from the US. The current movement is led by a group called Yes California, whose leaders have faced questions over links with Russia — cofounder Louis J. Marinelli is based in Moscow.

Though it’s mostly described as a fringe movement, it’s unclear how popular the idea of an independent California really is — one Reuters poll in 2017 found that as many as 1 in 3 people in the state supported a “peaceful withdrawal” from the US.

Calexit has been a favorite topic of both Iranian and Russian internet trolls in the past. On the night of the US elections in 2016, social media accounts with ties to Russia helped push the hashtag #calexit to the top of Twitter’s trending list, according to a BBC report.

“The M.O. now is to have a bunch of accounts together tweeting vociferously on a topic,” Jones said. “It’s a troll farm or an informal network of loyalists.”

Many of the most active Twitter accounts Jones analyzed were written in Farsi or had a connection to Iran, but other tweets were also written in English, Spanish, and Chinese. Some of the tweets referenced the coming of the Mahdi — a figure who in some Islamic traditions is fated to appear before Judgment Day. It’s unclear what the Mahdi has to do with Californian secession.

Jones said many of the accounts targeted high-profile verified accounts to try and spread the hashtag more quickly, including Joe Biden’s account and BBC Finance. But it’s not clear whether any high profile accounts picked up the hashtag as a result of the campaign.

Jones also downloaded more than 8,000 Instagram posts that used the #Calexit hashtag over several years. The hashtag was most active in two periods: The first coincided with Trump’s election in 2016, and the second was this month.

Iran’s influence campaigns come after the US decided to intensify sanctions against the country despite warnings that it could further cripple Iran’s medical infrastructure even as it grapples with coronavirus. Iran was the first country in the Middle East to be hit hard by the virus, and it currently has 85,996 confirmed cases with 5,391 recorded deaths.

Twitter and other social media platforms have pledged to crack down on disinformation ahead of the US presidential election this year. But the scope of the problem has exacerbated the task.

“Right now you have a double whammy of coronavirus and elections,” Jones said.