Apple argues that the FBI is seeking a "back door" into all iPhones as part of the San Bernardino probe
The government brief, in sharp contrast, argued it is a single case of technical assistance in an important national security investigation.
"The court's order is modest. It applies to a single iPhone and it allows Apple to decide the least burdensome means of complying," Justice Department lawyers wrote.
"It is a narrow, targeted order... The government and the community need to know what is on the terrorist's phone, and the government needs Apple's assistance to find out."