OAKLAND (AP) — Oakland voters must wait at least another day or two before learning who will be the city’s new mayor.

Thousands of provisional ballots being counted are taking longer than expected, Alameda County Registrar of Voters Dave Macdonald said Monday.

READ MORE: San Jose Police Release Video Of Suspect's Car In 2018 Khan Lieu Cold Case Murder

For the first time, Oakland is using ranked choice voting, where voters cast a first, second and third choice. The results of factoring in the second- and third-choice votes is incomplete, Macdonald said.

He didn’t know when the final tally would be completed.

KCBS’ Holly Quan Reports On Ranked Choice Voting:

The once-crowded, 10-candidate race is down to Oakland Councilwoman Jean Quan holding a slight lead over former state Sen. Don Perata, who was ahead after initial first-choice votes were tallied early last week.

Quan took the lead late last week after receiving a majority of second-choice votes from supporters of candidate and fellow Councilwoman, Rebecca Kaplan, who finished third.

READ MORE: Woman's Body Found Following Boating Accident Near Stockton

Standing outside City Hall on Monday, Quan said she remains cautiously optimistic.

“We are on the verge, we are hoping, of victory,” Quan said, as she prepared to host a “thank you” party for campaign staff and supporters that she’d hoped might become a victory celebration.

If Perata comes back to win, Quan said the fact that she made it even a close race is an “amazing victory for grassroots organizing in this city.”

Meanwhile, the Perata camp on Monday insisted they will wait and remain low-key until the results are final.

“We remain confident that Oakland voters’ first-choice preference for Mr. Perata will hold through once all of the ballots have been certified and counted,” Perata spokesman Rhys Williams said.

MORE NEWS: With COVID Cases Rising, Masks Now Required Indoors Regardless of Vaccination Status In Bay Area

(© 2010 CBS Broadcasting Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)