WASHINGTON (Reuters) - A hack on an Arizona election database during the 2016 U.S. presidential campaign was carried out by suspected criminal actors and not the Russian government, a senior Trump administration official told Reuters on Sunday.

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The official was responding to a report on CBS News’ “60 Minutes” citing an internal government document that Russian hackers successfully infiltrated computer systems associated with at least four U.S. states, including Arizona, leading up to the 2016 election.

Hackers working for the Kremlin breached systems in Illinois, a county database in Arizona, a Tennessee state website and an information technology vendor in Florida, according to the previously undisclosed Oct. 28, 2016, assessment from the Department of Homeland Security, according to the program.

But an administration official, speaking on condition of anonymity, said media reports had at times relied on outdated or incomplete information and conflated criminal hacking with Russian government activity. The cyber attack on Arizona was not perpetrated by the Russian government, the official said.

Media outlets including Reuters reported in August 2016 that the Federal Bureau of Investigation had detected Russian breaches of voter registration systems in Arizona and Illinois.

Reuters was not immediately able to confirm the authenticity of the DHS assessment, which would have been issued less than two weeks before the election. A DHS representative could not immediately be reached for comment.

U.S. intelligence agencies last year accused Russia of using hacking, false information and propaganda to disrupt the 2016 election and try to ensure Republican Donald Trump defeated Democrat Hillary Clinton. Russia denies interfering in the election. Trump has denied any collusion between his campaign and Moscow.

In June 2017, the news website The Intercept published a classified U.S. intelligence document that described a spear-phishing attack waged by Russian military intelligence on a U.S. election software company based in Florida.

The alleged breach of Tennessee’s state website had not been previously reported.

U.S. officials have repeatedly said publicly that at least 21 of the 50 states had experienced initial probing of their election systems from Russian hackers in 2016 and that a small number of networks were compromised.

While DHS has said there is no evidence any votes were actually altered, it has not publicly provided full details regarding which states experienced compromised systems or how deeply hackers penetrated them.

Americans vote in November in congressional elections, which U.S. intelligence officials have warned in recent weeks could be targeted by Russia or others seeking to disrupt the process.