The FBI and White House have said the request is limited to one iPhone.
But Apple says the software needed to comply with the FBI's request "simply does not exist".
Instead Apple says it would have to create a new version on the iPhone operating software, containing a back door to the device's encrypted data.
It argues that the lower court did not have the authority to force Apple to do that.
Apple also says no court had ever forced a company to weaken the security of its products to gain access to personal individual information.
"This case is about the Department of Justice and the FBI seeking through the courts a dangerous power that Congress
and the American people have withheld," the filing said
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