High-profile elections in Florida remain unresolved more than two days after the midterms vote, with the prospect of legal challenges, recounts and ballot reviews setting the stage for possible weeks of uncertainty.

The still-undecided races will not tip the balance in either chamber of Congress but include contests in parts of the country important to the futures of both parties and potentially to President Donald Trump’s re-election chances in two years.

In Florida’s US Senate race, Republican Governor Rick Scott, with his lead over Democratic incumbent Bill Nelson narrowing, filed lawsuits against election supervisors in two counties accusing them of failing to follow election law. A spokesman for Mr Nelson, Dan McLaughlin, said the lawsuits were politically motivated and “borne out of desperation.”

The Florida governor’s race between Republican Ron DeSantis and Democrat Andrew Gillum also appears headed for an automatic recount, after Mr DeSantis’ lead narrowed, despite Nr Gillum having already conceded.

Democrats on Tuesday won their first majority in the US House of Representatives since 2010, while Republicans appeared likely to expand their two-seat advantage in the US Senate.

Another cluster of races in the lower house where votes are still being finalised could add to the Democrats’ new majority, strengthening their hand as they seek to counter Mr Trump’s policies.

US midterm results: more diverse, more female and more progressive Show all 20 1 /20 US midterm results: more diverse, more female and more progressive US midterm results: more diverse, more female and more progressive Democratic candidate Ilhan Omar is celebrates with her husband's mother after she won a congress place, becoming the first Muslim woman to be elected into congress alongside Rashida Tlaib Reuters US midterm results: more diverse, more female and more progressive Democratic House candidate, from Kansas, Sharice Davids (left) and her mom Crystal celebrate after she won. Davids is the first lesbian Native American Congresswoman by beating Republican incumbent Kevin Yoder. Davids is one of several first-time female candidates that helped the Democratic Party takeover in the House of Representatives EPA US midterm results: more diverse, more female and more progressive Republican Marsha Blackburn celebrates after winning the race for senate in Tennessee. In doing so she became that state’s first female senator AP US midterm results: more diverse, more female and more progressive Supporters of Democratic House candidate Sharice Davids cheer and cry after learning she won EPA US midterm results: more diverse, more female and more progressive Ayanna Pressley beaome Massachusetts’ first black congresswoman by defeating 10-term Republican Michael Capuano AFP/Getty US midterm results: more diverse, more female and more progressive Republican candidate Young Kim has become the first Korean-American woman elected to Congress AP US midterm results: more diverse, more female and more progressive Democrat Jared Polis won his seat and became the US’s first ever openly gay governor AAron Ontiveroz/The Denver Post via AP US midterm results: more diverse, more female and more progressive Jean Kasselman (left) and Teresa Booker, supporters of Democratic candidate for Kansas' 3rd Congressional District Sharice Davids, react to election results Getty US midterm results: more diverse, more female and more progressive Republican Kristi Noem hugs a supporter after being announced as the new governor of South Dakota. Noem made history by being the first female governor of the state AP US midterm results: more diverse, more female and more progressive Gabierla Martinez and Cesar Delgado cheer on Democratic gubernatorial candidate Jared Polis REUTERS US midterm results: more diverse, more female and more progressive Alexandria Ocasio-Cortez became the youngest women ever elected to Congress, representing New York’s 14th congressional district AFP/Getty US midterm results: more diverse, more female and more progressive Democratic congressional candidate Rashida Tlaib celebrates with family and friends at her midterm election night party in Detroit after won and also became the nation’s first Muslim woman to congress alongside Ilhan Omar who was also elected Reuters US midterm results: more diverse, more female and more progressive Supporters of Democratic candidate for Kansas' 3rd Congressional District Sharice Davids react to election results Getty US midterm results: more diverse, more female and more progressive Already having become the first Native American woman to chair a state political party, Deb Haaland has now become the joint-first Native American woman to be elected to congress, alongside Sharice Davids Reuters US midterm results: more diverse, more female and more progressive Supporters of Alexandria Ocasio-Cortez cheer during her election night party in the Queens Borough AFP/Getty US midterm results: more diverse, more female and more progressive Young Kim hugs her son Alvin after she won a seat in congress AP US midterm results: more diverse, more female and more progressive Supporters of Alexandria Ocasio-Cortez cheer AFP/Getty Images US midterm results: more diverse, more female and more progressive Asma Mohammed and Ashley Fairbanks celebrate as results come in at Democratic congressional candidate Ilhan Omar's election night headquarters AP US midterm results: more diverse, more female and more progressive Democrat Deb Haaland hugs a voter REUTERS US midterm results: more diverse, more female and more progressive Supporters of Democratic House candidate from Kansas Sharice Davids cheer and cry after learning she won her race EPA

According to media outlet calls and the data company DDHQ, Democrats now have flipped 32 seats – nine more than they needed to take over the House – with seven Republican-held districts still too close to call, including four in California, where many ballots are yet to be counted.

In Florida, Mr Scott’s lead was narrowing on Thursday. Mr Nelson trailed by around 15,000 votes, or 0.18 per cent, within the state’s 0.25 threshold for a hand recount.

“The results are unknown,” said Marc Elias, an attorney for Mr Nelson’s campaign. Historically, Democrats tend to pick up votes in recounts, especially hand recounts, he said.

Mr Elias also pledged legal action if the campaign found that rejected ballots due to signature mismatches were disproportionately hurting minority voters.

Mr Scott’s lawsuits accuse Broward County Supervisor of Elections Brenda Snipes and Palm Beach County Supervisor of Elections Susan Bucher of mishandling the ballot count and preventing observers from having full access as votes are counted. Ms Snipes and Ms Bucher did not immediately respond to a request for comment.

Mr Scott also said he was asking the Florida Department of Law Enforcement to investigate.

“I will not sit idly by while unethical liberals try to steal this election,” Mr Scott told reporters.

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In the Florida governor’s race, Mr DeSantis’ lead had winnowed to about 38,500 votes on Thursday afternoon, or 0.47 per cent of the vote. The state conducts an electronic recount when the margin falls below 0.5 per cent.

Mr Gillum’s campaign said it was prepared for any outcome, including a recount.

“We want every vote counted,” Mr Gillum said in a video posted to Facebook on Thursday. “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.”