A hotly contested election race in San Francisco is still too close to call between Board of Supervisors president London Breed and former state Senator Mark Leno to become the city’s 45th chief executive. The race was prompted by the unexpected death of Mayor Ed Lee December 12, 2017.

Officials with San Francisco’s Department of Elections told the Los Angeles Blade Wednesday afternoon that the department is still processing roughly 88,000 thousand ballots, a number that may tip the scales in deciding the city’s next mayor.

NBC Bay Area reported initial results from Tuesday’s election indicated a large margin in first-place votes for Breed. However, once San Francisco’s ranked-choice voting system was taken into account with voters selecting their top three choices, Leno took the lead early Wednesday morning with 50.42 percent of the vote compared to 49.58 percent for Breed.

The city’s mayoral race had several high-profile candidates, including Supervisor Jane Kim and former Supervisor Angela Alioto.

Leno, a Democrat, was the first openly gay man elected to the California State Senate and also was a member of the California Legislative LGBT Caucus. He served until November 2016 representing the 11th State Senate district, which includes San Francisco and portions of San Mateo County. Prior to his election to the Senate, he served as a member of California’s State Assembly.

A longtime resident of San Francisco, Leno served as a member of San Francisco’s Board of Supervisors from 1998 until 2002 upon to his election to the State Assembly. In 2004, he authored the state’s first marriage equality bill, with support from Geoff Kors at Equality California and Kate Kendell of the National Center for Lesbian Rights.

Reporting by the staff of the Los Angeles Blade, NBC Bay Area, & wire service reports.