The Norwalk headquarters of the Los Angeles County Registrar-Recorder/County Clerk received a bomb threat via email, according to officials.
Authorities said that an investigation conducted at the office and Ballot Processing Center revealed no credible threats.
"We take all such threats seriously and are working closely with the FBI, state authorities and the Los Angeles County Sheriff's Department to ensure the safety of our staff and community and maintain uninterrupted operations,'' said Dean Logan of the Registrar-Recorder/County Clerk's office.
The Norwalk building was cleared Saturday afternoon and employees are set to return to work on Tuesday. Meanwhile, operations have resumed at the Ballot Processing Center and will continue on Sunday.
On Friday, registrars of voters' offices in Orange and Riverside counties were evacuated after similar bomb threat emails.
In Riverside, deputies responded just before 6:40 p.m. to the 2000 block of Gateway Drive and evacuated the Riverside County Registrar of Voters.
Around that same time, a similar threat was e-mailed to the Orange County Registrar of Voters in the 1300 block of Grand Avenue in Santa Ana, according to the Orange County Sherriff's Department.
Workers there were evacuated 15 minutes before ballot processing was scheduled to stop, officials said. Explosive detection dogs searched the building amid the investigation.
"The Orange County Registrar of Voters is committed to ensuring equal access to the election process, protecting the integrity of votes, and maintaining a transparent, accurate, and fair election system," Bob Page with the Registrar of Voters said in a statement. "We are working diligently to address this incident and keep all staff and members of the public who visit our office safe."
No explosives were found in those buildings.
Experts say the threats likely originated from Russia. More than 250 National Guard personnel were posted in 15 states on Election Day to ensure voting safety.
As ballots continue to be counted, closely watched races continue to flip, including one in Orange County and another in Los Angeles County -- the 45th and 27th Congressional Districts, respectively, according to the Saturday update.
More than half a million ballots remain to be processed in L.A. County.
The next update is expected on Sunday.
City News Service, Inc. contributed to this report.