SAN FRANCISCO (AP) — They're called national security letters and the FBI issues thousands of them a year to banks, phone companies and other businesses demanding customer information. They're sent without judicial review and recipients are barred from disclosing them.

On Friday, a federal judge in San Francisco declared the letters unconstitutional, saying the secretive demands for customer data violate the First Amendment.

The government has failed to show that the letters and the blanket non-disclosure policy "serve the compelling need of national security," and the gag order creates "too large a danger that speech is being unnecessarily restricted," U.S. District Judge Susan Illston wrote.