The Senate Intelligence Committee says that while Russian actors launched an "unprecedented" cyber campaign against the U.S. election system in 2016, it has seen no evidence that the interference affected the vote count.
The committee released the findings Tuesday in an unclassified summary of one of its reports on Russian interference.
The lawmakers found cyber actors affiliated with the Russian government targeted election systems in at least 18 states. In a small number of those states, the committee said the hackers "successfully" breached the voter registration database.
The report says that in those instances, the hackers had the ability to change registration data, but did not seem to have the capability to manipulate votes.
The lawmakers concluded the Department of Homeland Security's initial response to the election security threat in summer 2016 was "inadequate." It added that since then the department's cooperation with states has improved.
To ensure the upcoming 2018 midterm elections are kept secure, the committee recommended states use federal grant money to improve cybersecurity and that they quickly replace old voting machines. They suggest states purchase machines that produce paper ballots.