After hours of questioning Mark Zuckerberg in Washington, DC, in April, two US senators aren't done with the Facebook CEO. 

Sens. John Thune, a Republican from South Dakota, and Bill Nelson, a Democrat from Florida, sent more questions to Facebook on Tuesday, in the wake of more concerns over data from the world's largest social network. Thune, the chairman of the Senate Committee on Commerce, Science and Transportation, and Nelson, a ranking member on the committee, want to know if Zuckerberg lied during his initial appearance in April. 

The letter questioning his answers to Congress comes after The New York Times reported Sunday that Facebook gave companies like Apple and Samsung access to data without users' consent. In a blog post, Facebook disagreed with the report, saying the data agreements were necessary to build its product. Apple CEO Tim Cook said Monday the company doesn't have an agreement in place for access to Facebook users' data.

The data concerns are just the latest privacy issue for Facebook, which is still dealing with the fallout from its Cambridge Analytica scandal. In Thune and Nelson's first question for Zuckerberg, the lawmakers asked if the data partnerships mean the CEO was misleading in his remarks.

"In light of these manufacturing partnerships, is there anything about either this statement or any other part of your testimony before the Committees that you would like to amend?" the first question asks. 

Responding to a request for comment, a Facebook spokesperson said, "We look forward to addressing the Commerce Committee's questions."

The senators also want Zuckerberg to answer how Facebook verifies that its data partners aren't abusing that information, as well as what other manufacturers the social network partnered with. The lawmakers have given Zuckerberg and Facebook until June 18 to answer the questions. 

During Zuckerberg's testimony before Congress, he deferred many of the questions to his team, and said he'd be able to follow up on answers at a later time. Thune and Nelson said Zuckerberg hasn't submitted those responses yet. 

Cambridge Analytica: Everything you need to know about Facebook's data mining scandal.

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