Two weeks ago, Facebook admitted that a "shadowy Russian company" spent $100,000 on political ads targeting US Facebook users during the 2016 election campaign. At the time, Facebook turned in information about these ad buys to special counsel Robert Mueller, who is investigating Russian interference in the election.

Today, Facebook announced that it would also be turning the information over to Congressional investigators. And Mark Zuckerberg announced that Facebook would be stepping up its efforts to prevent foreign election interference in the future.

"The integrity of our elections is fundamental to democracy around the world," Zuckerberg said in a video posted to Facebook. "We can't prevent all governments from all interference. But we can make it harder."

One significant change will be greater transparency for political advertising. Facebook's platform allows advertisers to target different ads at different audiences. The company wants to make it easier for the public to understand how advertisers are using this capability.

"Not only will you have to disclose which page paid for an ad, but we will also make it so you can visit an advertiser's page and see the ads they're currently running to any audience on Facebook," Zuckerberg said.

Facebook will be beefing up its review process for ads in hopes of preventing foreign organizations from buying political ads during future elections. US election law prohibits foreigners from spending money to influence American elections.

Facebook is also planning greater focus on "election integrity" efforts. For example, "We have been working to ensure the integrity of the German elections this weekend, from taking actions against thousands of fake accounts, to partnering with public authorities like the Federal Office for Information Security, to sharing security practices with the candidates and parties." Zuckerberg says Facebook's staff for this kind of effort will double within the next year.

All of this underscores just how important Facebook has become to the political process. Facebook is now the most important source of traffic for many news sites, and its advertising platform has enormous reach. Facebook is scrambling to put in place policies and procedures to handle that vast influence in a responsible way.