Karen Handel, Republican candidate for Georgia's 6th Congressional District, speaks to supporters during a brief appearance at her election night party at the Hyatt Regency at Villa Christina in Atlanta, Georgia, US, June 20, 2017. [Photo/Agencies]

The first returns from the northern Atlanta suburbs have Republican Karen Handel and Democrat Jon Ossoff seesawing around 50 percent.

Turnout is on track to far exceed what is normal even for a November midterm and certainly beyond expectations for a special election. That reflects the attention and energy surrounding what has become the most expensive House race in US history as both parties vie for a key victory early in Donald Trump's presidency.

Handel celebrated the early numbers with her supporters at an area hotel, saying she improved on her April primary performance. "Everything we're seeing is incredibly encouraging," she said, though she noted it's "very, very early."Ossoff's camp is maintaining its confidence, noting that elections officials have said about 36,000 of the more than 140,000 early votes were from people who didn't cast ballots the first round. That makes it hard, they say, to know what the numbers actually mean.

Handel, a veteran Georgia politician, is fighting to claim a seat that's been in her party's hands since 1979. Ossoff, a 30-year-old first-time candidate, is hoping for an upset that would rattle Washington ahead of the 2018 midterm elections. Polls closed at 7 p.m.

The matchup has become a proxy for the national political atmosphere and a test of GOP strength early in Donald Trump's presidency, prompting record-breaking spending, a deluge of advertising and out-of-state volunteers, and more than a few tweets from the White House residence.

Voting technology activists also are keeping a close eye on the race after new details emerged last week about a security lapse at the center that manages Georgia's election technology. State officials say they're confident the technology is secure.

Democrats need to flip 24 Republican-held seats to reclaim a House majority; winning a conservative district like this one would embolden the party and serve notice to Republicans that a Democratic takeover is possible.

Handel and Ossoff have tried to say this race isn't about Trump or Washington, but the president and the GOP agenda on Capitol Hill have dominated the campaign.