Meanwhile, Gov. Rick Scott leads Sen. Four more contests - for state agriculture commissioner, a state Senate seat and two state House seats - are also likely headed for recounts.
Gillum has 49.1 percent, or 4,023,124 votes, while DeSantis has 49.6 percent, or 4,066,059 votes, for a margin of just under 43,000, according to NBC News. A 0.25-point vote margin prompts a more thorough manual recount.
The attorney for U.S. Sen.
"We believe at the end of this process Sen". It is AP policy not to call a race that is facing a recount.
The canvassing boards, which typically consist of the supervisor of elections, a county judge and a county commission member, review the ballots to see if the signature matches the one on file when the voter first registered, and to determine if the voter didn't already vote. But unless Gillum formally declines a recount, it would go forward if it gets within the needed margin - and his campaign staff did not look like it would turn down the opportunity.
"It has become clear there are many more uncounted ballots than was originally reported", Gillum's campaign said in a statement.
Democrats in three statewide races narrowed their deficits to Republican opponents as more ballots were counted Thursday, potentially setting up a lengthy recount process. "Our campaign, along with our attorney Barry Richard, is monitoring the situation closely and is ready for any outcome, including a state-mandated recount".
Gillum himself took to Facebook Live to address supporters, though he did not explicitly comment on if he hoped to win: "In spite of the fact that we're a little bit down in the numbers, we're hopeful that every single vote will be counted in this race", he said. But the actual timeline for a full, manual recount - which has never happened in Florida, even in 2000 - is unclear.
Marc Elias, a Washington lawyer on Nelson's team, said the candidate was demanding a recount.
"I would be dishonest if I didn't say this wasn't hard", he added.
More than 8.2 million ballots were cast in Florida's election, according to the state Division of Elections web site. "I'm not sure. I'm really not sure".
The Scott campaign, which declared victory Tuesday night, called Nelson "sad" for not conceding the race. The tweet included a link to an article about an unknown number of outstanding votes in Democratic-stronghold Broward County. He also told reporters on a conference call Thursday morning that there was significant undervoting in Broward County for the Senate race, where he said many voters didn't cast a vote for that race.
"We're doing this not just because it's automatic, but we're doing it to win", Elias said in a statement to the Times. "The intent is clear, but the machine couldn't pick it up".
But thousands of votes remained untallied.
When additional ballots began narrowing DeSantis' margin of victory on November 7, Gillum tweeted: "I'm looking forward to seeing every vote counted".
Voters who cast provisional ballots have until Thursday at 5 p.m.to verify their ID or provide other data to county officials to make their ballots count.
Thursday, Nov. 15: If a machine recount is ordered, the second round of unofficial returns is due from the counties at 3 p.m.
Florida law mandates that races where unofficial results show a margin of 0.5 percent or less will be subject to a machine recount, ordered by Florida Secretary of State Ken Detzner. "[We're] under a microscope".