Most of the accounts were posing as Democrats, the social media company said.
They were taken down in late September and early October.
Twitter was alerted to the accounts by the Democratic Congressional Campaign Committee (DCCC).
The DCCC was formed in response to the party's failure to respond to widespread false and negative information on social media about Hillary Clinton during the 2016 election, Reuters reported.
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Twitter believes that the network of now-deleted accounts was run from the US, CNN reported.
The DCCC is reported to be working with contractors to identify misinformation campaigns.
Last month the state of California signed legislation that bans the use of undeclared bots during elections.
The bill would make it illegal to use the bots to influence voting.
