WASHINGTON — The Justice Department, frustrated by its inability to unlock the iPhone of one of the attackers in the San Bernardino killings, demanded on Friday that a judge immediately order Apple to give it the technical tools to get inside the phone.

Apple’s refusal “appears to be based on its concern for its business model and public brand marketing strategy” rather than a legal rationale, prosecutors said in a court filing that further escalated the confrontation between the Obama administration and Apple.

“This is not the end of privacy,” the Justice Department declared, a mocking reference to Apple’s rationale for contesting the court order prosecutors obtained from a judge directing Apple to help them break into the phone.

The sharply worded, 25-page motion to compel Apple’s cooperation seemed aimed as much at swaying public opinion as influencing the federal magistrate judge in Riverside, Calif., who issued the order to Apple.