Story highlights At least five precincts in North Carolina had to switch to paper poll books earlier in the day

Thirty-seven percent of registered voters in Durham County are black

(CNN) North Carolina's Board of Elections on Tuesday extended voting in eight precincts by a variety of times, depending on the precinct, a victory for Democrats in the battleground state.

The times range from 20 to 60 minutes. The Durham County Board of Elections had requested a voting extension of 90 minutes county-wide after technical issues at several precincts earlier in the day forced election officials to switch to paper roll books from the electronic voter check-in system.

Earlier Tuesday, Democracy North Carolina, a nonprofit group, sued to extend hours in Durham County, which has a significant African-American population. The state elections board earlier extended voting in one precinct in Columbus County, a small county in the southeastern corner of the state. The county asked for 45 minutes but the state board allowed only 30 minutes extra voting time.

"As a result of these events, voting in Durham County was interrupted at multiple sites for at least one hour," Democracy North Carolina said in a statement.

By state rules, all voting locations in the county have to be affected for an extension of voting hours. The county has brought in 60 additional staff to work on providing more data to the state on how much the voting has been affected, Durham County Board of Elections spokesperson Briana Khan said.

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