The hack of the Florida contractor came on the heels of hacks in Illinois, in which personal data of tens of thousands of voters may have been stolen, and one in Arizona, in which investigators have started believing that the data of voters had been likely exposed.

The FBI, in the coming days, has been preparing to provide updated guidance to state elections officials around the US aiming to help them spot suspicious activity on their computer networks. Several states have reported attempted scans of their computer systems, which often is a precursor to a breach.

Previously, Illinois officials have said data on fewer than 90,000 people may have been affected by a breach there, and Arizona officials said they saw no indications hackers accessed data in their systems.

The vendor hack in Florida forced the FBI last week to coordinate an emergency call with county election supervisors who operate the election system in the perennial battleground state.

ABC News first reported that the Florida election information had been compromised.

Investigators believe a local contractor in California was the target of a hackers, but the systems accessed weren't related the elections.

A spokeswoman for the Florida Secretary of State said, "We currently have no indication of a Florida-specific issue. The Florida Voter Registration System database is secure. The Department of State does not utilize a vendor for voter registration services. The Department has in place many safeguards to prevent any possible attempts from being successful."

By Prakriti Neogi