ATLANTA — As Democrats ratcheted up their attacks on Georgia Republican Brian Kemp, he claimed Wednesday that results certified by county election officials confirm he has an "insurmountable lead" in the governor's race.

At a news conference, Georgia Democrats cast doubt on the legitimacy of any election count that ends with the former secretary of state being certified as the winner of a fiercely fought election against Stacey Abrams, who's seeking to become the first black woman elected governor in the U.S.

"We believe that Brian Kemp mismanaged this election to sway it in his favor," said Abrams' campaign manager Lauren Groh-Wargo, surrounded by Democratic lawmakers at the Georgia Capitol.

Democrats beyond Georgia have started to echo the notion that a Kemp victory would be illegitimate. Ohio Sen. Sherrod Brown said Wednesday that if Abrams loses it's because Republicans stole the election.

"If Stacey Abrams doesn't win in Georgia, they stole it. I say that publicly, it's clear," Brown, speaking at a briefing for the National Action Network.

Kemp's campaign, which has repeatedly called on Abrams to concede, repeated that call Wednesday, saying Abrams and her supporters have used "fake vote totals," ''desperate press conferences" and "dangerous lawsuits" to try to steal the election.

"After all of the theatrics, the math remains the same," Kemp campaign spokesman Cody Hall said in an email. "Abrams lost and Brian Kemp won. This election is over."

Since he declared himself governor last week and resigned as secretary of state, Kemp's lead has narrowed as counties have tabulated more ballots. And the numbers could change again as federal courts issue new guidance on counting certain provisional and absentee ballots.

Groh-Wargo said Tuesday that the Abrams campaign believes she needs a net gain of 17,759 votes to pull Kemp below a majority threshold and force a Dec. 4 runoff. Kemp's campaign said even if every vote that Abrams campaign is arguing for is granted by the courts and counted for her, she cannot overcome his lead or force a runoff.

The Associated Press has not called the race.

Meanwhile, U.S. District Judge Steve Jones on Wednesday ruled that the secretary of state must not certify the state election results without confirming that each county's vote tally includes absentee ballots on which the voter's date of birth is missing or incorrect.

The order stems from a request in a lawsuit filed Sunday by the Abrams campaign. But Jones also rejected the campaign's other requests.

He declined to extend the period during which evidence could be submitted to prove the eligibility of voters who cast provisional ballots. He also declined to order that provisional ballots cast by voters who went to a precinct in the wrong county be counted.

The lawsuit was one of several election-related complaints filed before multiple federal judges.

U.S. District Judge Leigh May ordered Gwinnett County election officials Tuesday not to reject absentee ballots just because the voter's birth year is missing or wrong. She also ordered the county to delay certification of its election results until those ballots have been counted.

Jones' ruling effectively extended May's order to the other 158 counties in Georgia.

U.S. District Judge Amy Totenberg late Monday ordered state officials not to do their final certification of election results before 5 p.m. Friday.

State law sets a Nov. 20 deadline, but secretary of state's office elections director Chris Harvey testified last week that the state had planned to certify the election results Wednesday, a day after the deadline for counties to certify their results. He said that would allow preparations to begin for any runoff contests, including those already projected in the races for secretary of state and a Public Service Commission seat.

Totenberg's order left untouched the county certification deadline. Candice Broce, a spokeswoman for secretary of state's office, said Wednesday that all counties but Gwinnett have certified their totals.