Apple being forced to unlock a terrorist's iPhone is an unprecedented grab for power by the government, company says in court

'No court has ever authorized what the government now seeks, no law supports such unlimited and sweeping use of the judicial process, and the Constitution forbids it,' Apple said in the documents.

Apple has said that the US government is seeking “dangerous power” by forcing the company to unlock a terrorist’s phone, in landmark legal filings that challenge the Obama administration and the FBI.

The company has responded to an order issued last week, which compels Apple to help weaken the security on a phone used by the San Bernardino killer and give access to its contents.

Apple argues that doing so would set a dangerous precedent and put its users in danger. Now it has filed court documents arguing that the decision is also forbidden by the constitution and represents an unprecedented grab for power by the US government.

The documents are the first official response by Apple to an order that it has expressed public anger at and vowed to fight up to the Supreme Court. They use many of the same arguments that have been voiced by executives and experts since the ruling came out, including Tim Cook’s claim that the government was asking Apple to create “the software equivalent of cancer”.

"No court has ever authorized what the government now seeks, no law supports such unlimited and sweeping use of the judicial process, and the Constitution forbids it," Apple said in the documents.

The Justice Department is proposing a "boundless interpretation" of the law that, if left unchecked, could bring disastrous repercussions, the company warned in a memo submitted to Magistrate Sheri Pym that aggressively challenges policy justifications put forward by the Obama administration.

"The government says: 'Just this once' and 'Just this phone.' But the government knows those statements are not true," lawyers for Apple wrote.

They said that if Apple were required to build the software the FBI wants, "criminals, terrorists and hackers will no doubt view the code as a major prize and can be expected to go to considerable lengths to steal it."

A hearing is scheduled for next month.

The dispute broke into public view last Tuesday when Pym directed Apple to help the FBI gain access to a phone used by one of the assailants in the San Bernardino, California, attacks.

Federal agents haven't been able to open the phone of Syed Farook because they don't know the passcode. The Justice Department wants Apple to create specialized software for the iPhone that would bypass some security features so that the FBI can try as many passcodes as possible without the data being erased.

The filing was made the same day that FBI Director James Comey defended the government's approach during separate appearances on Capitol Hill, where he stressed that the agency was seeking specialized software for only one phone as part of an investigation into an act of terror that left 14 dead.

But Apple said the specialized software the government wants it to build does not currently exist and "would require significant resources and effort to develop," including the work of six to 10 engineers working two to four weeks. The magistrate judge suggested in her ruling that the government would be required to pay Apple's costs.

Apple compared forcing it to create software that doesn't exist to weaken the iPhone's locks to forcing a journalist to publish false information to arrest a fugitive or forcing another software company to implant a virus in a customer's computer so the government could eavesdrop.

And it accused the government of working under a closed courtroom process under the auspices of a terrorism investigation of trying "to cut off debate and circumvent thoughtful analysis."

Apple pointedly noted the U.S. government itself fell victim to hackers, when thieves stole the personal information of tens of millions of current and former federal workers and their family members from the U.S. Office of Personnel Management.

Additional reporting by Associated Press