Georgia officials counted the final votes of the nation’s turbulent 2020 election season early on Wednesday as polls closed in two critical races that will determine control of the US Senate.

The two Senate runoff elections are leftovers from the November general election, when none of the candidates hit the 50% threshold.

Democrats need to win both races to seize the Senate majority — and, with it, control of the new Congress when President-elect Joe Biden takes office in two weeks.

President Donald Trump encouraged his loyalists to turn out in force even as he undermined the integrity of the electoral system by pressing unfounded claims of voter fraud to explain away his own defeat in Georgia.

As of Wednesday morning, it was too early to call the close races.

In one contest, Republican Kelly Loeffler, a 50-year-old former businesswoman who was appointed to the Senate less than a year ago by the state’s governor, faced Democrat Raphael Warnock, 51, who serves as the senior pastor of the Atlanta church where Martin Luther King Jr grew up and preached.

The other election pitted 71-year-old former business executive David Perdue, a Republican who held his Senate seat until his term expired on Sunday, against Democrat Jon Ossoff, a former congressional aide and journalist.

At just 33 years old, Mr Ossoff would be the Senate’s youngest member.

Mr Biden and Mr Trump campaigned for their candidates in person on the eve of the election, though some Republicans feared Mr Trump may have confused voters by continuing to make wild claims of voter fraud as he tries to undermine Mr Biden’s victory.

The president has assailed Georgia secretary of state Brad Raffensperger, a Republican, repeatedly for rejecting his fraud contentions and raised the prospect that some ballots might not be counted even as votes were being cast on Tuesday afternoon.

State officials said there were no major problems with voting on Tuesday.

Gabriel Sterling, a top official with the Georgia secretary of state’s office, said voting was smooth across the state with minimal wait times, though lines of around an hour built up in Republican-leaning Houston, Cherokee, Paulding and Forsyth counties.

While they have no merit, Mr Trump’s claims about voter fraud in the 2020 election have resonated with Republican voters in Georgia.

About seven in 10 agree with his false assertion that Mr Biden was not the legitimately elected president, according to AP VoteCast, a survey of more than 3,600 voters in the runoff elections.

Election officials across the country, including the Republican governors in Arizona and Georgia, as well as Mr Trump’s former attorney general, William Barr, have confirmed that there was no widespread fraud in the November election.

Nearly all the legal challenges from Mr Trump and his allies have been dismissed by judges, including two tossed by the Supreme Court, where three Trump-nominated justices preside.

Even before Tuesday, Georgia had shattered its turnout record for a runoff with more than 3 million votes by mail or during in-person advance voting in December. The state’s previous record was 2.1 million in a 2008 Senate runoff.

Democrats counted on driving a huge turnout of African Americans, young voters, college-educated Georgians and women, all groups that helped Mr Biden win the state.

Republicans, meanwhile, have been focused on energising their own base of white men and voters beyond the core of metro Atlanta.

If Republicans win either seat, Mr Biden would be the first incoming president in more than a century to enter the Oval Office facing a divided Congress.

In that case, he would have little shot for swift votes on his most ambitious plans to expand government-backed health care coverage, address racial inequality and combat climate change.

A Republican-controlled Senate also would create a rougher path to confirmation for Mr Biden’s Cabinet picks and judicial nominees.

With many Republicans skeptical of the outcome even before the results were announced, Georgia Republican Party chair David Shafer said the party was closely watching the vote counting.

“Other than the good Lord above, we are trusting no one,” Mr Shafer said during an election night event at an Atlanta hotel, noting that 8,000 Republican volunteers were observing voting and counting.

“We will have eyes on every part of this process, and we are doing everything in our power to restore the confidence of the people in the integrity of our elections.”