At a Glance: Calls in US, UK to Probe Facebook, Data Firm

She wants Zuckerberg's assurances that Facebook is prepared to take the lead on security measures that protect people's privacy -- or Congress may step in. Sen. Mark Warner of Virginia, the senior Democrat on the Senate Intelligence Committee, also wants Zuckerberg to testify. But Intelligence Committee Chairman Richard Burr, a Republican from North Carolina, won't commit to asking Zuckerberg to appear. Republicans on the Commerce Committee also have sent letters requesting information from Facebook and Cambridge parent SCL Group.