US sees no ‘specific or credible threat’ to disrupt midterm polls: Official

American officials are not seeing any credible threats aimed at the country's voting machines or poll books during the U.S. midterm elections, a senior federal cybersecurity official told reporters on Tuesday.

"We see no specific or credible threat to disrupt election infrastructure," the official told reporters during a scheduled briefing just as Election Day was beginning.

The official, who briefed journalists on condition of anonymity, said that did not mean there would be no hiccups. U.S. officials in New Jersey's Mercer County, for example, have said on the county's Facebook page that there were "issues with voting machines" there and that poll workers were on hand to help voters.

"We see issues every Election Day," the U.S. official said, speaking generally. "Such incidents would not affect a person's ability to cast a ballot or know that their ballot was counted accurately."

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Election security has emerged as a key issue in the United States after officials found Russia interfered in the 2016 U.S. presidential election with a campaign of hacking and propaganda intended to hurt Hillary Clinton's chances of winning against Donald Trump.

The Cybersecurity and Infrastructure Security Agency (CISA) has set up an Elections Day Operations Center with public- and private-sector partners across the country to monitor the midterms, it said in a statement on Monday.

"In recent years, election officials have had to contend with increasing disinformation from foreign adversaries, which can cause confusion about election infrastructure and undermine voters' faith in the process," Kim Wyman, the security agency's senior election security advisor, said in a statement last week.

"Now, when something goes wrong - and with 8,800 election jurisdictions across the country, something will go wrong somewhere - the innocuous can be made to look nefarious."