Voting systems in over three dozen states -- nearly twice as many as previously thought -- bore the brunt of a Russian cyberattack during the November presidential election, Bloomberg reported Tuesday.

Russian hackers set their sights on election systems in 39 states during the course of meddling in the contest, according to the report. In some instances, the report said, they gained access to state-level voter data and other records including the names and partial Social Security numbers of millions of registered voters.

"In Illinois, investigators found evidence that cyber intruders tried to delete or alter voter data. The hackers accessed software designed to be used by poll workers on Election Day, and in at least one state accessed a campaign finance database," Bloomberg reported Tuesday.

The U.S. intelligence community concluded in January that Russian hackers interfered in the election by compromising the internet accounts of people affiliated with Democratic presidential candidate Hillary Clinton and then publishing their personal correspondence prior to Election Day amid the course of conducting a broader Kremlin-ordered influence campaign.

Although the government publicly denied Russia targeted or compromised systems involved in vote tallying, people with direct knowledge of the U.S. investigation into the matter told Bloomberg that Russian hackers most certainly sought out voter databases and software systems in several states.

The FBI declined to comment on the government's probe, but people familiar with state investigations offered Bloomberg previously unreported details involving the scope of the cyberattack.

In Illinois, for example, hackers managed to breach a database containing the names, dates of birth, genders, driver's licenses and partial Social Security numbers of 15 million people, Bloomberg reported.

Federal investigators ultimately traced a digital footprint found in the aftermath of the Illinois intrusion with attempts to breach election systems used in 38 other states, according to one of Bloomberg's sources.

"Last year, as we detected intrusions into websites managed by election officials around the country, the administration worked relentlessly to protect our election infrastructure," Eric Schultz, who was a spokesman for President Obama, told Bloomberg. "Given that our election systems are so decentralized, that effort meant working with Democratic and Republican election administrators from all across the country to bolster their cyberdefenses."

Russia has repeatedly denied interfering in the election, contrary to the findings of the U.S. intelligence community.