Russian hackers tried unsuccessfully to access Washington's election systems before the 2016 general election, according to the state Secretary of State's Office.
State Election Commission spokesman Chris Whitmire said the Department of Homeland Security called officials in SC on Friday to tell them the state was not hacked.
The secretary of state's office also says it uses a paper-based system that lets officials examine a voter's intent and can hand-count a race if necessary.
The North Carolina agency says it's still reviewing what caused Election Day problems in Durham County with software that checked whether voters were registered to cast ballots and asking federal authorities to clarify whether they've ruled out Russian interference.
Haas said the commission is seeking more specific information, including when the scanning activity occurred in 2016. "This was a scan and many computer systems are regularly scanned". He said hacking attempts are not uncommon.
Wisconsin was one of 21 states notified Friday of the attempted hacking.
The disclosure Friday comes as the commission was working on ramping up its security measures.
A Bloomberg News story in June reported that during the 2016 elections, hackers hit voting systems or databases in 39 states.
Trump won Wisconsin by fewer than 23,000 votes.
Haas says security provided by the state successfully protected Wisconsin's systems.
Meanwhile, the state is moving ahead with implementing a new election security plan by early 2018.