ATLANTA (AP) — Republican Sen. Kelly Loeffler of Georgia and Democrat Raphael Warnock are headed to a Jan. 5 runoff in the special election for Loeffler’s U.S. Senate seat.

They’re the top two finishers in a crowded field that also included Republican Rep. Doug Collins. But neither was able to get the 50% threshold needed in order to win outright.

Loeffler, a wealthy businesswoman, was appointed last year to replace retiring Sen. Johnny Isakson. Warnock is pastor of the Atlanta church where the Rev. Martin Luther King Jr. preached and is trying to become Georgia’s first Black U.S. senator.

Warnock gained the backing of Democratic leaders including former President Barack Obama. That helped clear the field for Warnock on the Democratic side while Loeffler and Collins battled it out on the right.

The winner will serve the rest of Isakson’s term. The seat goes on the ballot again in 2022.

THIS IS A BREAKING NEWS UPDATE. AP’s earlier story follows below.

ATLANTA (AP) — In an election where control of the U.S. Senate could be on the line, Georgia is the only state with both seats on the ballot — two opportunities for Republicans to hold their ground; two opportunities for Democrats to make gains.

Republican Sen. David Perdue faced Democrat Jon Ossoff in a race that public polling has shown to be very close. In the other, Republican Sen. Kelly Loeffler faced a crowded field that includes GOP Rep. Doug Collins and Democrat Raphael Warnock in a special election for the seat Loeffler was appointed to 10 months ago.

Collins conceded defeat late Tuesday as incomplete election returns showed him lagging behind both Loeffler and Warnock. He tweeted: “I just called @KLoeffler and congratulated her on making the runoff. She has my support and endorsement.”

The Associated Press has not made a call in that race.

Warnock told supporters late Tuesday that he expected to advance to a January runoff and promised to fight for “ordinary people” worried about keeping their jobs and healthcare.

“It never mattered much to me, and it doesn’t matter tonight, who I have to run against," Warnock said, "because I’ve always been clear about who I’m running for.”

Democrats haven't won a Senate race in Georgia in two decades. But ongoing population growth around Atlanta and shifting demographics that have made the state less white — along with dissatisfaction with President Donald Trump in the suburbs — have helped fuel hope among Democrats that the state is in play.

There's a chance both races could stretch into next year, with runoffs to be held on Jan. 5 if no candidate surpasses 50% this time.

Both sides have poured huge amounts of money into the races, and record numbers of people cast ballots early, some facing hourslong lines. Georgia has also seen a large increase in absentee ballots cast by mail.

Voting on Tuesday was off to a fairly smooth start despite some technical issues, and wait times were relatively short — a big change from the June 9 primaries when poll worker shortages, coronavirus restrictions and trouble with new voting machines led to chaos and long lines at some polling places, especially around Atlanta.

Perdue, a former business executive and a close Trump ally, faces Ossoff, a documentary film producer who launched his political career with an unsuccessful 2017 run for Congress. Their race has been characterized by sharp attacks but relatively moderate political positions.

Perdue has sought to cast Ossoff as backing a “radical socialist agenda,” while Ossoff has portrayed Perdue as a “corrupt” Washington insider.

Loeffler, a super-wealthy businesswoman, and Collins, a four-term congressman who is one of Trump's most visible defenders in the House, have been locked in a battle for voters from the conservative base of the GOP. Meanwhile, Warnock, pastor of the Atlanta church where Martin Luther King Jr. preached, has mostly floated above the fray after consolidating support among Democrats.

With a runoff highly likely, the bitterly personal tone of Loeffler and Collins’ attacks could make it difficult for the candidates — and their supporters — to mend fences in time for the January runoff, University of Georgia political scientist Charles Bullock said.

If Loeffler advances, “her challenge would be to simply get Republicans back behind her,” Bullock said. “That’s a real risk.”

Joey Odom of Savannah voted early for Perdue, saying his support for the coastal city’s seaport has helped the local economy. A 58-year-old sales representative for a manufacturer, Odom said he typically votes Republican. He gave Trump and Perdue high marks for their efforts to reopen businesses during the coronavirus pandemic.

“I feel for some of the states that are still essentially shut down while ours is up and running to an extent,” Odom said.

In Decatur just outside Atlanta, Linnea Pace, 57, voted early for Ossoff. She said she didn’t vote for any Republicans.

“I live in a Black, middle-class neighborhood. I haven’t seen any Republican come into my neighborhood and ask me what is going on,” Pace said, noting that Ossoff had visited her church.

Pace also said she believes Perdue sold stock to benefit himself when he first learned the coronavirus could devastate the U.S. economy.

“He knew that pandemic was coming,” she said.

Both Perdue and Loeffler were among senators whose stock trades, made just before the virus caused a downturn in the markets, came under scrutiny. Both denied wrongdoing, saying the trades were made by independent advisers and were ultimately cleared by the Senate Ethics Committee.

Regardless, their opponents made the trades a central line of attack. Collins accused Loeffler of “pandemic profiteering,” while Ossoff accused Perdue of having “profited from the pandemic while he downplayed the risk.”

The top Democrats outraised the Republican incumbents, but the Republicans were also buoyed by outside spending. More than $160 million has been spent on television and digital advertising by candidates and outside groups in both races.

In the Atlanta suburb of Marietta, John Benson showed up nearly an hour before polls opened at the Cobb County Civic Center, waiting in near freezing temperatures. He said he wants senators who are not afraid to stand up to the president.

“Since Donald Trump been in office, it’s been like a lot of them have been scared to speak up,” Benson said.

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Bynum reported from Savannah, Georgia. AP writer Jeff Martin contributed from Marietta, Georgia.

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Find AP’s full election coverage at APNews.com/Election2020.