UPDATE: Nelson is doing several events in the Panhandle today, we're told, after initial publication of this item. The campaign says Nelson was doing ad production work on Friday and Saturday.

He dropped a bombshell then disappeared.

Sen. Bill Nelson has remained out of public view since raising alarms about Russian hacking last Wednesday. His campaign isn't responding to reporters and Nelson hasn't commented except for a statement released from his Senate office just before 5 p.m. Friday.

"I and several of my Senate colleagues are trying to make sure Florida officials are aware of the ongoing Russian threat so they take the steps necessary to safeguard our elections. It's unfortunate that some Florida officials would try to use this issue for personal, political gain," Nelson said.

He was referring to Gov. Rick Scott, who on Friday used a campaign stop in Tampa to accuse his November rival of either disclosing classified information or making things up.

[Rick Scott demands Bill Nelson provide proof of Russian election meddling]

But Nelson got some cover from his Senate colleagues, including the chairmen of the Senate Intelligence Committee, who issued statements that did not confirm what Nelson said about Russians having "penetrated" some county election systems ahead of the midterms but also did not contradict them and told the state to take things seriously.

Sen. Marco Rubio, also an Intel Committee member, reacted similarly.

The 75-year-old Democrat is still exposed politically. "Bill Nelson can't hide forever and Floridians deserve an explanation now," said the NRSC on Monday.

Late Friday, Florida Secretary of State Ken Detzner sent a letter to the Department of Homeland Security and FBI asking for detail about what Nelson vaguely described. He asked for a response by Monday.

So far, the state hasn't said whether it received information.

Check back for updates.

Scott appeared on Fox News.