General Keith Alexander, director of the National Security Agency, suggested he was open to the idea but that officials were trying to determine a way to disclose that information without jeopardising FBI investigations.
We just want to make sure we do it right, that we don't impact anything ongoing with the FBI. I think that's the reasonable approach, Alexander told the Aspen Security Forum in Colorado, when asked about the letter.
Together with LinkedIn, Yahoo, Microsoft, Twitter and many others, the firms asked for more transparency of secret data gathering in the letter addressed to Alexander as well as US President Barack Obama, attorney general Eric Holder and national security leaders in Congress.
Tech firms have been scrambling to assert their independence after documents leaked last month by former US security contractor Edward Snowden raised questions about how much data on their clients they handed over to the government to aid its surveillance efforts.