The Justice Department notified a federal judge Friday that it intends to pursue a lawsuit in Brooklyn against Apple, seeking to force the company to open the iPhone of a convicted New York drug dealer.

In February, the judge denied the FBI's request to force Apple to open the New York phone, but the Justice Department appealed that ruling. The judge then asked the government whether its position would change after the FBI managed — without the help it was seeking from Apple — to open an iPhone used by Syed Farook, one of the San Bernardino attackers.

On Friday, government lawyers said they still need Apple's help opening the Brooklyn phone. Its application in that case "is not moot, and the government continues to require Apple's assistance in accessing the data it is authorized to search by warrant," they said in a letter to Judge Margo Brodie.

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The method a third party provided to open the San Bernardino phone won't work on the Brooklyn phone, federal officials said.

FBI Director James Comey said Wednesday that the newly acquired method used on the San Bernardino device works on only a narrow range of phones — the model 5c running a specific version of the Apple mobile operating system.

The Brooklyn phone, by contrast, is a model 5s running an older version of iOS.

A key difference between the two cases is that while Apple bitterly resisted the government's demand that the company write new software to help unlock Farook's phone, no such technical barrier exists in unlocking the Brooklyn phone.

Read More: FBI Accessed iPhone in Terror Case, Raising More Questions About Key Issues

"Apple told our folks that they could extract data from the specific phone at issue," a law enforcement official said Friday. "One of their lawyers told the judge at a hearing that would take only a matter of hours."

Apple has provided the kind of help sought in Brooklyn in the past, but it stopped doing so last October, when a judge there questioned the legal mechanism the Justice Department was employing to compel Apple's assistance.

Apple lawyers said on Friday that they were disappointed, but not surprised, by the government’s decision to continue to pursue the case in Brooklyn. They said it raised the question many asked and the government repeatedly denied in the San Bernardino case: Whether the FBI was interested in pursuing the issue in court to set a precedent that could be used to crack phones in other investigations.

The company will file its next response to the government on April 14 in New York. Lawyers for Apple described the Brooklyn case and the government’s request to extract and decrypt data on the phone as a routine drug investigation, and clearly not a terrorism case as in California.

Apple does not plan to sue the government to get more information about the technique the FBI says was used on Farook’s device, the lawyers for the company said, adding that Apple will continue to focus on improving the security of its devices.