Thirty-seven privacy rights groups and private companies such as Facebook, Foursquare, Google, and Yahoo have banded together and signed a letter opposing the new surveillance powers that the FBI is set to receive.

These organizations are worried that a proposed amendment to the 2017 Intelligence Authorization Act. If approved, the amendment would broaden the type of data the FBI would be able to collect using National Security Letters (NSLs).

NSLs are legal documents issued by the FBI that can force a company to reveal details about one of its clients without a court warrant. The EFF claims that the FBI issued more than 300,000 NSLs in the last ten years since NSLs were introduced.

FBI wants NSLs to better cover online activities

Until now, the FBI could use NSLs to collect information on suspects such as "name, address, length of service, and local and long distance toll billing records."

US Senators have proposed a new amendment to the Electronic Communication Transactional Records (ECTRs) via the 2017 Intelligence Authorization Act that would expand the types of data that could be collected through NSLs without the need of a court-issued warrant.

This update would allow the FBI to solicit data such as "browsing history, email metadata, location information, and the exact date and time a person signs in or out of a particular online account."

Collected data can give clues about the target's personal, offline life

Privacy groups and tech companies argue that this could allow the FBI to infer information about their clients' "political affiliation, medical conditions, religion, substance abuse history, sexual orientation, and [...] movements throughout the day."

The FBI has gotten a lot of bad reputation after many companies had admitted they were gagged by subpoenas about the number and the contents of the NSLs they received.

Recently, Yahoo revealed the content of a National Security Letter for the first time, along with information about the total number of NSLs it received and the number of targeted accounts.

Below is the full letter, signed by organizations such as the Electronic Frontier Foundation, Access Now, American Civil Liberties Union, Human Rights Watch, Government Accountability Project, and more.