With the U.S. midterm elections days away, researchers have identified what they called a coordinated network of Twitter accounts that are pushing false and misleading narratives about election integrity with hashtags like #VoterFraud.

They found a core of 200 accounts that tweeted or were mentioned in tweets more than 140 million times over the last year, according to a research report published Saturday.

The findings don't necessarily reflect a reprise of the Russian influence efforts in the 2016 election, nor is the tweeting clearly driven by automated bots, researchers say. But the network of accounts, which sounds off at relatively regular intervals — even at times when there is nothing about the topic in the news — has helped create an echo chamber to justify state-level ballot restrictions despite little evidence of actual voter fraud.