Stressing that next week will certainly be a test for Facebook, Zuckerberg said election integrity is and will be an ongoing challenge even after November 3.
Four years ago, Facebook's security teams were looking for traditional threats like hacking.
"But what we ended up seeing was something new -- coordinated interference campaigns, using fake accounts that tried to spread misinformation and discord. Since then, we've built the most advanced systems in the world to find and remove these threats, and it shows in the numbers," Zuckerberg told analysts during the company's earnings call on Thursday.
In the years since, Facebook has taken down more than 100 networks, including from Russia, Iran and China.
"We block millions of potentially abusive accounts every day. No other company has systems nearly as advanced," the Facebook CEO claimed.
"The changes we've made in the last four years helped us protect the integrity of more than 200 different elections around the world, including in the EU, India and Indonesia. And they've been important for stopping abuse ahead of next week's vote in the US," he added.
Zuckerberg mentioned steps the company has taken to make ads transparent.
"Anyone who wants to run a political or social issue ad has to go through our authorisation process first. And between March and September, we rejected ads 2.2 million times, before they could run, for trying to target the US without authorization," he informed.
"We are very focused on voter suppression. We are working closely with experts in the space, including civil rights leaders".
Facebook has helped 4.4 million people register in the US.
"We also estimate that in September, we helped 100,000 people sign up to be poll workers," Zuckerberg said.