WASHINGTON (CNN) -- In a dramatic break with the Bush administration, the Justice Department on Friday announced it is doing away with the designation of "enemy combatant," which allowed the United States to hold suspected terrorists at length without criminal charges.

Officials will no longer use the designation of "enemy combatant," the Justice Department said.

In a court filing in Washington, the department said it is developing a new standard for the government's authority to hold detainees at the Guantanamo Bay detention facility in Cuba.

The announcement says the Justice Department will no longer rely on the president's authority as commander in chief, but on authority specifically granted by Congress.

And the government document says that individuals who support al Qaeda or the Taliban are detainable only if the support was "substantial."

The category of "enemy combatant" had been an important aspect of the Bush administration's legal construct for dealing with terrorism suspects.

The government describes its new policy position in a memo submitted to the U.S. District Court in Washington, D.C., in a case dealing with Guantanamo Bay detainee litigation that began during the Bush administration. Watch CNN's Jeanne Meserve explain the reversal »

In the document, the Obama administration provides a more limited definition of who may be held at Guantanamo Bay:

"The president has the authority to detain persons that the president determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, and persons who harbored those responsible for those attacks," the document says.

"The president also has the authority to detain persons who were part of, or substantially supported Taliban or al-Qaida forces or associated forces that are engaged in hostilities against the United States or its coalition partners, including any person who has committed a belligerent act, or has directly supported hostilities, in aid of such enemy armed forces."

The Justice Department did not say how many of the approximately 240 detainees now at Guantanamo may fall within the new definition. The new construct clearly allows for the continued detention of admitted 9/11 mastermind Khalid Sheikh Mohammed and a handful of his acknowledged al Qaeda operatives.

The government says that it is developing a comprehensive detention policy and that the new definition applies only to prisoners at Guantanamo Bay and not at other military prison facilities.

"This position is limited to the authority upon which the government is relying to detain the persons now being held at Guantanamo Bay. It is not, at this point, meant to define the contours of authority for military operations generally, or detention in other contexts," the government said.

Attorney General Eric Holder is overseeing the administration's review of what to do with each of the Guantanamo prisoners.

In the court document submitted by his lawyers, it is clear that the prosecutors will consider each case on its particular merits.

"It is neither possible nor advisable to attempt to identify in the abstract the precise nature and degree of 'substantial support,' or the precise characteristics of 'associated forces,' " according to the document.

The government said it will need to apply the new definition and the concrete facts in individual cases.

In a 12-page explanation of its position, the government memo says the the Justice Department will look to the congressionally passed Authorization for the Use of Military Force and to international treaties, including the Geneva Conventions, to make decisions about holding prisoners.

But the government also said that because those treaties were developed for conflicts between the armed forces of nation states, new rules will have to be developed to fit al Qaeda and Taliban prisoners who were previously designated as "enemy combatants."

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