A decision by elections officials in Georgia’s third-largest county to drastically reduce the number of early-voting sites for the crucial U.S. Senate runoffs has drawn the ire of several civil rights and voting rights groups.

Cobb County, which borders Atlanta on the west, will offer five polling sites when early voting begins Dec. 14. For the Nov. 3 general election, it had 11 locations to serve the county’s more than 537,000 voters.

Advocates warned in a letter Monday that the closures “will be harmful to Cobb County’s Black and Latinx voters” because many of the shuttered polling sites are located in minority neighborhoods. The next closest sites are between five and 12 miles away, and public transportation options in that area of the county are inadequate, the letter stated.

“We urge you to maintain eleven advance voting locations for the upcoming runoff election,” read the letter, signed by the NAACP Legal Defense and Educational Fund and five advocacy groups.

But Janine Eveler, Cobb County elections director, said she doesn’t have enough staff trained in advance voting to operate the same number of polling places for the runoff, which has taken on national significance because it will determine which party controls the Senate.

“We lost several of our advance voting managers and assistant managers due to the holidays, the workload and the pandemic,” Eveler responded in a letter to the groups. She added that “the remaining team members who agreed to work would do so only if the hours were less onerous. … We are at the end of the election cycle and many are tired or just unwilling to work so hard, especially during this time of year.”

In an interview Monday, Eveler said the workers are seasonal employees hired and trained for statewide elections. She said that many of them were “not willing to work 14-hour days for six days a week for three weeks.”

During early voting for the general election, voters in Cobb County waited for periods of five to 10 hours, according to some news reports, another reason cited in the NAACP letter that officials should keep more polling places open.

Eveler said the county will add more check-in stations that were used in the general election, which should get voters into the booth more quickly. She also noted that voters will have only three contests on the runoff ballot: the two Senate races and a seat on the Georgia Public Service Commission.

The state’s two Republican senators, David Perdue and Kelly Loeffler, are defending their seats from Democrats Jon Ossoff and Raphael Warnock. The runoff became necessary because neither Perdue, who is seeking a second term, nor Loeffler, who is running to complete the term of former senator Johnny Isakson (R), got more than 50 percent of the vote in last month’s general election.

If they win, Republicans will retain control of the Senate; if the Democrats win, they will control the chamber with Vice President-elect Kamala D. Harris as the tiebreaker.

Cobb County helped Joe Biden become the first Democratic presidential nominee to win Georgia since 1992. Biden beat President Trump in Cobb 56 percent to 42 percent — similar to the margin by which Republican Mitt Romney won the county in 2012 over President Barack Obama, 55 percent to 43 percent. Four years ago, Democrat Hillary Clinton edged Trump by two percentage points — 48 to 46 percent.

In the Senate contests last month, Ossoff bested Perdue by 11 percentage points in Cobb County, while Warnock got 38 percent of the vote to 25 percent for Loeffler in a field of 21 candidates for the special election.

Both parties are pouring massive amounts of money and people into the state for the races, with both sides hustling to get their voters back to the polls in the midst of a pandemic and the holiday season. Although officials expect fewer than the 5 million voters who cast ballots in the general election, turnout could be more robust than in previous runoffs because of the stakes for control of Washington.

Michael Pernick, one of the lawyers for the NAACP Legal Defense Fund, said in an interview that the groups were evaluating their next steps to “protect communities of color in Cobb County that would have significant difficulty accessing advance voting if that plan goes through.” He said that most of Cobb’s Black and Latino voters live in the southern portion of the county, where four locations have been folded into one site that is “all the way at the bottom of south Cobb and is not accessible to many of the voters in those communities.”

Eveler said she did not think voters of color would be adversely affected. She said the early-voting sites are located in “each quadrant of the county,” and while acknowledging that some voters will be inconvenienced, she said that “there are other options for voting.” She said voters could use absentee ballots or show up on Jan. 5, when all of the county’s 145 precincts will be open.

Lauren Groh-Wargo, chief executive of Fair Fight Action, the group started by former Georgia gubernatorial candidate Stacey Abrams to advocate voting rights, said in a statement that “Black voters in particular” faced long waits during early voting in Cobb County for the general election. Fair Fight also argued that other large metro counties have kept the same number of early-voting locations.

“In an election that is sure to see high turnout and high voter enthusiasm, this is unacceptable,” Groh-Wargo said, adding that county elections officials “must do better and live up to their responsibility to their voters.”

The other groups that signed the letter are All Voting is Local, Georgia, the Southern Poverty Law Center Action Fund, the Georgia NAACP, Black Voters Matter Fund and the American Civil Liberties Union of Georgia.