The FBI believes “at least one Florida county” was infiltrated in 2016 with malicious software sent out by Russian intelligence agents, according to the Mueller Report released Thursday.

But the Florida Secretary of State’s office maintained its elections systems weren’t hacked, adding that the FBI hasn’t told the state which county they believe was compromised.

The report states that in November 2016, Russian intelligence officials “sent spearphishing emails to over 120 email accounts used by Florida county officials responsible for administering the 2016 U.S. election.”

The emails contained an attached Word document with malicious “Trojan” software that would have permitted Russian intelligence to access the infected computer, the report states.

On Thursday, Volusia County sent to the Orlando Sentinel an image of the email without its infected attachments. It purported to be from Tallahassee-based VR Systems.and asked elections office officials to “please take a look at the instructions for our modernized products. Best regards, VR Systems Inc.”

Volusia County elections supervisor Lisa Lewis said Thursday the office opened one of the infected emails in 2016, but not the attachment needed for the malicious software to compromise its systems.

Sarah Revell, a spokeswoman for Secretary of State Laurel Lee, said in a statement Thursday the department “has no knowledge or evidence of any successful hacking attempt at the county level during the 2016 elections.”

“Upon learning of the new information released in the Mueller Report, the Department immediately reached out to the FBI to inquire which county may have been accessed, and they declined to share this information with us,” Revell wrote. “The Department maintains that the 2016 elections in Florida were not hacked. The Florida Voter Registration System was and remains secure, and official results or vote tallies were not changed.”

The new information in the report goes a step beyond the initial reporting in 2017 that Florida counties were at least targeted.

An Intercept report based on a leaked National Security Agency document revealed that the Russian intelligence hack targeted VR Systems, which provided the software used in Volusia, Osceola and 50 other Florida counties to identify voters when they go to a polling location.

At the time, Amber Smith of the Osceola County Elections Office said her office did not receive the phishing email, while then-Seminole Supervisor of Elections Michael Ertel said Seminole did not use the specific type of software targeted,

The current Seminole County elections supervisor, Chris Anderson, confirmed in a statement Thursday that the county did not receive the phishing email described in the report.

Orange County elections supervisor Bill Cowles also said Orange didn’t use VR Systems’ software in 2016.

Volusia County Supervisor of Elections A full image of the phishing email sent to Volusia County Elections Office in 2016, including attachments. The Mueller Report states the FBI believes Russian intelligence accessed at least one Florida county via this email. Volusia County Supervisor of Elections A full image of the phishing email sent to Volusia County Elections Office in 2016, including attachments. The Mueller Report states the FBI believes Russian intelligence accessed at least one Florida county via this email. Volusia County Supervisor of Elections (Volusia County Supervisor of Elections)

In South Florida, Palm Beach County did not use VR Systems software in the 2016 elections, said spokeswoman Alison Leitheuser on Thursday.

Miami-Dade used VR systems for voter check-in and registration, but not for posting election night results, officials said. Broward County used VR Systems software for posting its election night results.

Broward County Supervisor of Elections Pete Antonacci said his information technology director was not aware of any phishing attempts over the November 2016 election.

Robert Rodriguez, assistant deputy elections supervisor in Miami-Dade County, also said his office has no indications “of possible or actual elections systems compromise from internal monitoring or external parties.”

Back in September 2016, elections officials in all of Florida’s 67 counties took part in a call with FBI officials, who warned about possible hacking attempts meant to tamper with the election.

Cowles said that while Orange didn’t contract with VR Systems in 2016, the County Commission approved a contract with the company in the past month and will switch over to VR Systems by the end of the year.

Cowles said 65 of 67 Florida counties now use the company’s software, up from 52 in 2016, and the last two counties, Palm Beach and Sarasota, are in negotiations to do so as well.

Last year, then-U.S. Sen. Bill Nelson, D-Fla., warned that Russians had gained access to Florida voter data. But he declined to identify which counties had been penetrated, saying the information was classified. No other officials backed up Nelson’s claim. He could not be immediately reached on Thursday.

While he didn’t comment on the specifics offered by Nelson last year, U.S. Sen. Marco Rubio, R-Fla., warned repeatedly that “state election systems are potentially vulnerable to Russian cyber attacks.” Rubio wasn’t available for comment on Thursday.

The Mueller Report also stated that on August 22, 2016, the Russian intelligence-affiliated “Guccifer 2.0” group “transferred approximately 2.5 gigabytes of Florida-related data stolen from the DCCC [Democratic Congressional Campaign Committee] to a U.S. blogger covering Florida politics.”

The Wall Street Journal reported in 2017 that blogger Aaron Nevins of “HelloFLA” set up a Dropbox account to receive exactly that amount of data from Guccifer 2.0. The data included Democratic strategies for Florida congressional candidates.

South Florida Sun Sentinel staff writers Anthony Man and Lawrence Barszewski contributed to this report. slemongello@orlandosentinel.com, 407-418-5920, @stevelemongello, facebook/stevelemongello