WASHINGTON – Sen. Bill Nelson declared vindication Friday over his still unsubstantiated claim that Russians hacked into some county election systems in Florida, pointing to a news report that stated there is a "classified basis for Nelson's assertion."

The Florida Democrat tweeted a breaking news alert from NBC News. "Bill Nelson wasn't making things up when he said Russians hacked Florida election systems," it read.

The report was based on "three people familiar with the intelligence." There's no official confirmation of Nelson's claim.

BREAKING - NBC NEWS: Bill Nelson wasn't making things up when he said Russians hacked Florida election systems https://t.co/7TgaPIB69o — Senator Bill Nelson (@SenBillNelson) August 17, 2018

Gov. Rick Scott, who is challenging Nelson for re-election, has accused Nelson of leaking classified information or simply fabricating the story, first disclosed to the Tampa Bay Times more than a week ago.

The Times has reported how top Republicans in Washington, including Senate Intelligence Committee Chairman Richard Burr and Sen. Marco Rubio, have issued statements that neither confirm or contradict what Nelson said.

[Bill Nelson: The Russians have penetrated some Florida voter registration systems]

The Florida Department of State did not respond to the NBC News report.

Instead, a spokeswoman pointed to a Thursday letter sent to Nelson from Secretary of State Ken Detzner and Paul Lux, president of the Florida State Association of Supervisors of Elections, asking for evidence to support his claims.

"The Department of State has no evidence to support his claims at this time. We look forward to his response," the spokeswoman said Friday, responding for the governor as well.

As governor, Scott has a security clearance and could have requested a briefing from Washington officials but did not. A spokesman said that Detzner's office was handling communication with federal authorities.

Republican groups hammering away at Nelson reacted to the report by questioning if the Democrat "broke the law" by revealing classified information.

Rules for the Senate Intelligence Committee do say senators are not to disclose material and can be referred to the ethics committee if they do.