SACRAMENTO (CBS13) — The race between Democratic incumbent Ami Bera and Republican challenger Doug Ose isn’t finished, and the fight for the 7th Congressional District is growing more heated by the day.

The race is still too close to call, with Ose holding a 2,000-vote lead.

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Now, both sides are trying to change the outcome of the election by challenging ballots.

Spokespeople for both the Ose and Bera campaigns say they want all the votes counted accurately. But behind the scenes there is controversy.

A roomful of observers from both the Ose and Bera campaigns are closely watching the count. Office workers authenticate signatures of absentee ballots.

So far in the race, Sacramento County Registrar of Voters Jill LaVine says more than 3,000 ballots have been challenged.

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“I have never had that happen here before,” she said.

Once challenged, the vote has to be reviewed by a supervisor.

“Which really slows our whole process down,” she said.

Elections officials say there could be enough outstanding ballots to change the outcome of the race.

No new numbers are expected to be released until Monday afternoon.

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The county has until December to certify the results.