The United Nations is standing behind Apple in the company’s fight against the FBI over whether the federal government can compel the iPhone-maker to create a backdoor into iOS.

In a letter written in support of Apple’s case, U.N. Special Rapporteur David Kaye says that if the feds are successful, it would infringe on citizens’ right to freedom of expression.

Pointing to a U.N. report he published last year, Kaye argues encryption is “fundamental to the exercise of freedom of opinion and expression in the digital age.” He goes on to slam the FBI’s demands as completely unnecessary.

“Given that the Government has multiple, alternative technical and operational measures to conduct this investigation, it is unclear that the Government’s motion to compel Apple to create software to enable access to this iPhone is necessary for this particular investigation.”

Kayes questions whether the FBI went to other agencies for help in unlocking the iPhone 5c that belonged to one of the San Bernardino terrorists that killed 14 people. Director James Comey told the House Judiciary Committee that the FBI had exhausted all internal resources and queried other agencies for help on unlocking the iPhone. However, some of the congressional representatives on the committee weren’t convinced the FBI has tried everything.

“My concern is that the subject order implicates the security, and thus the freedom of expression, of unknown but likely vast numbers of people, those who rely on secure communications,” warns Kaye. “This is fundamentally a problem of technology, one where compromising security for one and only one time and purpose seems exceedingly difficult if not impossible.”

A number of other companies and individuals are expected to file amicus briefs in support of Apple today. The husband of San Bernardino survivor Anies Kondoker has submitted a letter in Apple’s favor, arguing that there’s probably not any data on the iPhone 5c in question, since it was a work phone and employees knew they could be monitored.

Briefs from the ACLU, Access Now, Wickr Foundation, the App Association and more are available to view on Apple’s website.