Google CEO Sundar Pichai has used his Twitter account to lent support to Apple in the debate over encrypted iPhones. Pichai praised Apple CEO Tim Cook for writing an "important" letter that speaks out against the FBI’s decryption demands. "Forcing companies to enable hacking could compromise users’ privacy," Pichai wrote. Forcing tech companies enable hacking of customers' devices and data "could be a troubling precedent," Pichai added.

The FBI wants Apple to open a "backdoor" to its iOS in order to break into the phone of Syed Rizwan Farook, one of the shooters in a December attack that killed 14 people in San Bernadino, California.

Magistrate Judge Sheri Pym of the U.S. District Court for the Central District of California ordered Apple to provide assistance to the FBI, including by providing signed software to help the FBI try different passcodes on a locked iPhone 5c running iOS 9, without triggering the auto-erasure feature in the phone after 10 failed attempts.

However, Apple says that such action would enable force attacks on password-protected iPhones.

Mozilla and WhatsApp also back Apple in its "fight" with the FBI.