TALLAHASSEE — One week after Election Day, high-stakes contests in Florida and Georgia remained mired in uncertainty amid expanding legal fights and political wrangling that could further prolong the counting of ballots.

In Florida, where elections officials are conducting machine recounts in the races for Senate, governor and agriculture commissioner, Sen. Bill Nelson (D) and the Democratic Senatorial Campaign Committee filed a suit in federal court Tuesday evening seeking to extend the deadline to finish the count in all 67 counties.Separately, Nelson and the state party went to court to try to loosen the rules for a manual recount as both parties braced for the ultra-close Senate race to come down to a hand inspection of ballots.

On Capitol Hill, Senate Minority Leader Charles E. Schumer (D-N.Y.) urged Florida elections officials to take as much time as they need to tally votes, even if they blow past a key deadline. He also demanded that Gov. Rick Scott (R), who is narrowly ahead of Nelson in the Senate race, recuse himself from the recount. Scott’s campaign swiftly rejected that notion, which is the subject of a suit expected to be heard in federal court this week.

In Georgia, a federal judge late Monday barred the secretary of state’s office from immediately certifying the state election results there to give voters a chance to address questions about their provisional ballots — a move that further prolongs the hard-fought Georgia governor’s race between Democrat Stacey Abrams and Republican Brian Kemp.

And from Maine to California and in between, 10 House races were still unresolved — leaving the size of the Democrats’ majority undetermined as new lawmakers reported to Capitol Hill for orientation.

The unsettled races extended the intense partisan combat that gripped the country during this year’s campaigns.

In Florida, the Senate race will determine the size of the GOP’s majority in 2019 and shape the power structure in the nation’s largest swing state. Elections officials face a deadline of 3 p.m. Thursday to complete machine recounts of three statewide races. Observers expect the margins in the Senate and agriculture commissioner contests to remain narrow enough after the machine counts to trigger hand recounts.

Stacks of ballots were recounted by machines Nov. 13 in Broward County, Fla., for the Senate race between Gov. Rick Scott (R) and Sen. Bill Nelson (D). (Monica Akhtar/The Washington Post)

The suit filed by Nelson on Tuesday aims to stop the state canvassing board from certifying the results before all 67 counties complete their machine and manual recounts. In their filing, Democrats noted that officials in Palm Beach County have said it may be impossible to meet the deadlines.

On Tuesday night, Susan Bucher, the supervisor of elections for Palm Beach County, announced that vote-counting machines had overheated and stopped working — requiring staff to redo a recount of 174,900 early-vote ballots that took a day and a half to get through the first time.

“We are disappointed by the mechanical problems,” Bucher said. “We’re working 24/7 to get the job done.”

The defendants of the latest suit by Democrats include the members of the Florida Elections Canvassing Commission, which is required to certify the final results by Nov. 20. Under Florida law, if local officials fail to meet that deadline, the state will certify the previously reported, pre-recount totals.

“This process is about one thing — making sure that every legal ballot is counted and protecting the right of every Floridian to participate in our democracy. And that is to have their ballot counted and to count as they intended,” Nelson told reporters in Washington.

Standing next to Nelson, Schumer said officials “should have all the time they need to count every Floridian’s ballot, to make sure the candidate with the most votes is actually seated in January, even if the vote count has to go beyond Sunday.”

“It looks like @SenBillNelson is cutting out the middle man and letting @ChuckSchumer speak directly for him,” Scott’s campaign said on Twitter. “Chuck - we won’t let DC lawyers and N.Y. senators steal this election from the people of Florida.”

Tim Cerio, an attorney for Scott, said on a call with reporters that “the idea that deadlines don’t matter in elections is an in­cred­ibly partisan and irresponsible comment.”

There is also building tension in Georgia, where Abrams is hoping to force a runoff with Kemp, who is leading by about 59,000 votes in the governor’s race.

Tuesday was the deadline for Georgia’s 159 counties to finalize their election results, and the secretary of state had planned to certify them Wednesday. But U.S. District Judge Amy Totenberg said late Monday that the secretary of state’s office could not do so before Friday and had to “immediately establish and publicize on its website a secure and free-access hotline or website for provisional ballot voters to access to determine whether their provisional ballots were counted and, if not, the reason why.”

Kemp, who resigned as secretary of state late last week and declared victory, said there are not enough outstanding votes to keep him from winning. Lauren Groh-Wargo, Abrams’s campaign manager, told reporters that as of Tuesday, Abrams needed 20,595 votes to force a runoff and 18,259 to initiate a recount.

The secretary of state’s office has reported that 21,190 provisional ballots were cast in the Nov. 6 election.

The Republican advantage in the Senate race in Florida is even slimmer. Scott led Nelson by fewer than 13,000 votes after the initial count, or 0.15 percent. A margin of 0.25 percent or smaller would trigger a manual recount.

The Senate election has caught the attention of President Trump, who leveled another unsubstantiated allegation Tuesday against administrators in Broward and Palm Beach counties and suggested Nelson should bow out.

“The characters running Broward and Palm Beach voting will not be able to ‘find’ enough votes, too much spotlight on them now!” the president tweeted.

Trump’s comments marked the latest attempt by Republicans, including Scott, to try to undermine confidence in the process. But state officials said they have seen no signs of criminal activity or fraud in the vote tallying.

The recount kicked off over the weekend in many Florida counties. But Broward, the state’s second-most-populous county, began counting ballots only Tuesday morning. Republicans have complained about the pace in the Democratic stronghold.

About midday at the Broward elections office in Lauderhill, Joe D’Alessandro, director of election planning and development, carried in five bins of recounted ballots with “under votes” and “over votes,” to be set aside for closer scrutiny in the event of a hand recount.

On those ballots, voters did not choose a candidate or chose more than one. The chair of the canvassing board, Broward Judge Betsy Benson, instructed him to put the bins in a corner “where they will always be in public view.” She asked whether more bins would be coming.

“There will be a lot more,” D’Alessandro replied.

By midafternoon, Broward County had finished recounting early votes. But it still had more than 400,000 ballots left to tally.

“We will complete the recount,” said Brenda Snipes, the elections supervisor in Broward County. “There’s never been a deadline that we’ve missed.”

Asked about the latest attack from Trump, Snipes said: “Well, I don’t have a treasure trove for going out digging on the beach somewhere to find any votes.” She said she had never met Trump “other than seeing him from television, and he hasn’t met me.”

After Snipes noted that she was appointed to replace another black woman who was removed from office, she was asked whether she thought her race was a factor in the criticism of her management. “It’s sort of hard to rule out,” she said.

And she hinted that she is not likely to run for reelection in 2020. “It is time to move on,” said Snipes, a Democrat.

Several pro-Trump Facebook pages and one Twitter account on Monday posted the home address and phone number of Snipes — a tactic called “doxing” that often is a step toward harassment of people in the public spotlight and is prohibited by Facebook, Twitter and most other online platforms.

Facebook confirmed Tuesday that it had removed personal information about Snipes after the incident was reported to the company. Twitter declined to comment. Two tweets from an account visible Tuesday morning were deleted by noon.

In neighboring Miami-Dade County, the most populous in the state, Mayor Carlos Gimenez said Monday he was “very confident we’re going to get this done on time.”

But several variables could complicate the recount — most notably the mounting legal disputes.

One of the new suits filed by Democrats on Tuesday seeks to widen the latitude of canvassers to determine voter intent when and if they start examining ballots manually.

In another case, a court Wednesday will hear a request from Nelson to count absentee and provisional ballots that were not tallied because voters’ signatures did not match their voter registration records — which could affect as many as 4,000 absentee ballots.

Separately, Scott withdrew his lawsuit against Palm Beach County seeking to impound the election equipment not in use for the recount, a day after a judge denied a similar request in Broward County.

While Scott has been a vocal critic of Democrats during the recount, Republican gubernatorial nominee Ron DeSantis has been much quieter. DeSantis, a close Trump ally, has a more comfortable margin over Tallahassee Mayor Andrew Gillum (D). Democrats and Republicans are not anticipating a hand recount in the governor’s race.

Congressional officials were also keeping tabs on the House races that have yet to be called. They include contests in Maine’s sprawling 2nd District, where Rep. Bruce Poliquin (R) filed a lawsuit rejecting the state’s tabulation of ranked-choice ballots, and a pair of Republican-held districts in California where the GOP candidates were narrowly ahead but losing ground. In Utah, Rep. Mia Love (R) trailed her Democratic opponent, though her deficit narrowed Tuesday.

Sullivan reported from Tallahassee, Reinhard from Lauderhill, Williams from Washington and Rozsa from Riviera Beach, Fla. Amy Gardner in Fort Lauderdale, Fla., and Craig Timberg and Mike DeBonis in Washington contributed to this report.