Tim Cook says Apple's refusal to unlock iPhone for FBI is a 'civil liberties' issue

• 'This is about much more than a single phone or a single investigation'
• FBI escalates war with Apple: 'Marketing bigger concern than terror'

Apple boss Tim Cook told his employees on Monday that the company's refusal to cooperate with a US government to unlock an iPhone used by Syed Farook, one of the two shooters in the San Bernardino attack, was a defense of civil liberties.

The Apple CEO called for the Department of Justice to withdraw its order in an email to staff sent the morning after the FBI director, James Comey, said the company should comply in order to help bring justice to the victims.