BERLIN — German officials say there’s no sign of concerted cyberattacks aimed at influencing the outcome of the country’s upcoming election, but warned Wednesday against giving the all-clear yet.

Security officials have warned over the past year that the Russian government in particular might attempt to destabilize Germany by promoting extremist parties in Sunday’s vote. German Chancellor Angela Merkel has been the driving force behind maintaining international sanctions against Russia over its involvement in the conflict in Ukraine.

“We don’t see that (Russian President Vladimir) Putin has meddled in the election campaign,” Germany’s interior minister, Thomas de Maiziere, told mass-circulation daily Bild in an interview Wednesday. “Maybe they didn’t try. Maybe it’s still coming.”

A spokesman for the interior ministry, Johannes Dimroth, told reporters that security officials regularly see cyberattacks against government bodies and politicians in Germany, but these haven’t caused any major damage.

“Luckily we can’t report any large-scale attacks. But in our view we haven’t reached the point in time where we can give the all-clear,” Dimroth said, citing the last-minute release of emails from Emmanuel Macron’s party on the eve of the French presidential election in the spring.

Researchers recently have observed a more subtle attempt to influence the German election in the shape of an increasing number of fake Twitter accounts backing the nationalist Alternative for Germany party.

Luca Hammer, a data analyst working for the civil society group Fearless Democracy , said he identified a group of apparently automated Twitter accounts — so-called bots — that began flooding the social network with racist and anti-government messages earlier this month.

The bots appeared to mimic a tactic used by far-right activists in the United States to promote Donald Trump’s campaign during the U.S. presidential election last year. Unlike in the U.S., though, Twitter isn’t widely used in Germany.

“Overall, it’s hardly relevant,” Hammer told The Associated Press. “But lots of journalists and politicians are on Twitter and for them it might create a misleading image of what the public thinks.”

The view was echoed by Laura Rosenberger, a senior fellow at The German Marshall Fund of the United States. The Washington-based think tank recently launched a digital tool to monitor the Twitter activity of a network linked to the German-language account of Kremlin-controlled news website Sputnik.

“Even if many people aren’t seeing this directly, the ideas we see pushed around Twitter are making it into the mainstream,” Rosenberger said.

Alternative for Germany, or AfD, has by far the biggest presence on social media . The party uses it to send a steady stream of anti-immigrant and anti-Merkel messages to hundreds of thousands of followers on Twitter and Facebook.

Rosenberger said many of the messages seen coming from the Sputnik-linked Twitter network reflect the positions of AfD.

“But we are also seeing a pattern in Germany where a lot of messages aren’t about particular parties or candidates, but about sowing divisions in society and trying to exploit them,” she said.

Hammer, the data analyst, said political ads designed to target specific groups on Facebook may have a greater effect on Germany’s election. Earlier this month, it was revealed that hundreds of phony Facebook accounts, likely run from Russia, spent about $100,000 on ads aimed at stirring up divisive issues during the 2016 U.S. presidential campaign.

Facebook has refused to allow researchers to analyze its content in the same way as Twitter, said Hammer.