Sen. Amy KlobucharAmy Jean KlobucharThe Hill's Morning Report: Trump walks back from 'send her back' chants Biden, Harris set for second Democratic debate showdown Poll: McConnell is most unpopular senator MORE (D-Minn.) called on Facebook founder and CEO Mark ZuckerbergMark Elliot ZuckerbergHillicon Valley: Trump seeks review of Pentagon cloud-computing contract | FTC weighs updating kids' internet privacy rules | Schumer calls for FaceApp probe | Report says states need more money to secure elections Maxine Waters says her committee will call in Zuckerberg to testify about Libra Hillicon Valley: Lawmakers struggle to understand Facebook's Libra project | EU hits Amazon with antitrust probe | New cybersecurity concerns over census | Robocall, election security bills head to House floor | Privacy questions over FaceApp MORE to explain the extent of the damage done in a breach of user data by research firm Cambridge Analytica, and how it is going to fix the problem. 

The firm, a political and corporate information consultant used by the Trump campaign in 2016 for voter research, was suspended from the social media site after Facebook found that it had used the personal data of nearly 50 million users for campaign research. 

ADVERTISEMENT

Klobuchar, a ranking member on the Senate Judiciary Committee and former prosecutor, said on CNN's "New Day" that Zuckerberg "should explain to the American people how this happened, how many people were hurt, and most importantly, how they're going to fix it."

The senator's comments follow her calls for the Facebook chief to testify before the committee in response to reports that Facebook discovered the firm did not delete the user data gathered in 2015, and used it in support of the Trump campaign. 

"You have a product which has been designed without a lock or without an alarm, and big surprise, some of the bad guys have gotten in," Klobuchar added. 

Facebook has also handed over information on the breach to Congress and the special counsel investigating Russian interference in the election, after it was discovered that the firm had met with Russian executives in the lead-up to the election.