Apple previously had been given three extra days to respond to the order, with a Feb. 26 deadline. Apple CEO Tim Cook and other tech executives denounced a court order this week amid a renewed debate over how much access tech companies should give authorities to investigate or prevent attacks.
The Justice Department filed a motion Friday to compel Apple to assist investigators in accessing data on the Apple iPhone used by Syed Rizwan Farook, one of the shooters in the 2015 attack, which left 14 people dead. The phone is owned by Farook's former employer, the San Bernardino County Department of Public Health.The department has agreed to allow investigators to search the device.
"Apple's current refusal to comply with the court's order, despite the technical feasibility of doing so, instead appears to be based on its concern for its business model and public brand marketing strategy," the motion said.
Apple did not immediately respond to CNBC's request for comment about the Justice Department's latest move.
Earlier this week, Cook bashed the request, calling it "chilling." He argued that the government could use it to "extend this breach of privacy and demand that Apple build surveillance software" to gather personal data.
"The United States government has demanded that Apple take an unprecedented step which threatens the security of our customers. We oppose this order, which has implications far beyond the legal case at hand," Cook wrote.
The government has insisted that the order would only apply to the phone in question. However, it has stirred concerns about possible requests for a "back door" around Apple's encryption, which many in Silicon Valley fear could leave systems more vulnerable to attacks.
Apple would effectively have to create a new version of its operating system and install it on the phone to make it easier to unlock. A federal magistrate ruled this week that the tech giant would have to create the software within a certain time frame.
The legal debate will continue to play out in the coming weeks, as Apple's opposition to the motion is due Feb. 26. A hearing is set for March 22 in California.
A senior Apple executive said the Justice Department was disregarding civil liberties with the request, according to Reuters. The executive added that Congress, rather than court, would be the appropriate place for the encryption debate. Leaders of the House Energy and Commerce Committee on Friday invited Cook and FBI Director James Comey to testify on encryption.
— CNBC's Eamon Javers and Jim Forkin contributed to this report.