President Carter has "directed the attorney general, with the assistance of the FBI," to take over the leaks to the press about the Pentagon's Stealth project, in which new aircraft are being developed which supposedly will be largely "invisible" to enemy radars.

The president's order is contained in a letter to Rep. Samuel S. Stratton (D-N.Y.), chairman of the subcommittee on investigations of the House Armed Services Committee.

In that letter, which the congressman's office made available yesterday, Carter says he "shares the committee's dismay of the rash of disclosures of national security information that recently occurred."

Though the president mentioned a rash of disclosures, the letter seems to indicate that the order of the attorney general and FBI pertains only to the Stealth program and to leaks about that project to The Washington Post, Aviation Week and Space Technology magazine, and ABC News.

Carter said he had asked Defense Secretary Harold Brown to cooperate with the attorney general and with the Stratton subcommittees' own inquiry, and said the results of the Justice Department's probe will be made available to the subcommittee.

Thus far, the only publicly known investigation of Stealth leaks is an internal one by the defense intelligence service, which has no authority, according to defense officials, to take its probe much beyond the Pentagon.

The controversy over published reports in mid-August about Stealth has turned out to be one of the biggest and longest-running battles of the election campaign.

Republican challenger Ronald Reagan and many of the defense specialists supporting him claim that the Carter administration intentionally leaked enough information about the project to justify a subsequent press conference by Defense Secretary Brown confirming the program and thus making the administration look better on defense matters than its record might otherwise indicate.

The administration has denied this, and in his letter to Stratton the president wrote: "I can, and do, state unequivocally that neither I, nor any member of White House staff, acting under my direction or authority, have engaged in or authorized the leaking of classified information concerning the Stealth program."

The president's disclaimer and other portions of the letter describing administration action came in response to a letter Stratton sent to Carter on Sept. 12 on behalf of the subcommittee.

Stratton asked Carter whether he "directed or approved any release of information by the secretary of defense on the Stealth program" and if so, to provide the committee "with a full description of the circumstances surrounding his decision."

Concerning Brown's role, Carter replied that the secretary has "scrupulously followed" guidance given him in earlier years to maintain security around the program as tightly, and for as long, as possible.

Carter said that earlier this year Brown expressed the belief that increasing budget demands for Stealth would soon require expanded briefings for Congress about the project in connection with next year's spending.

Then came the major press reports about Stealth in mid-August, shortly before the Democratic convention.

In his letter Carter said that, on Aug. 17, Brown advised him that in view of the "serious press leaks" he had concluded that the timetable for acknowledging the existence of Stealth technology had to be advanced while continuing to protect the security of the technical details. Brown's controversial press conference followed soon after.

Carter said that he did not direct Brown to take that step in acknowledging Stealth, but that he approved it, agrees with Brown's decision and "continues to believe that his judgment in this matter was correct."