WASHINGTON (AP) -- President Eisenhower kept secret from U.S allies his orders that authorized military commanders to launch retaliatory nuclear attacks from their territory, declassified documents reveal.

The instructions to the commanders, declassified last month and published Friday by the independent National Security Archive, authorized nuclear strikes to repel a major invasion of U.S.-occupied territory by conventional forces. Such a scenario could have turned a theater war in Europe into a nuclear conflict.

It has long been known that Eisenhower was the first president to ``predelegate'' nuclear authority to senior U.S. commanders in cases where they could not contact him in time to authorize nuclear counterattacks. Presidents Kennedy and Johnson maintained the practice.

The newly declassified documents are the first to include a set of instructions and the first to attach Eisenhower's signature to such an order.

In a Nov. 2, 1959, letter to Deputy Secretary of Defense Thomas Gates, Eisenhower reviews his original May, 1957, authorization, and in the process he stresses the need for secrecy.

``I cannot overemphasize the need for the utmost discretion and understanding in exercising the authority set forth in these documents,'' he tells Gates. He urges him to brief the commanders ``in a small symposium, consisting only of the commanders concerned.''

Among those listed as authorized to issue such commands are commanders of U.S. forces in Europe, the Caribbean, the Atlantic, the Pacific and, in some cases, commanders of naval forces in the eastern Atlantic and Mediterranean..

At a June 27, 1958, meeting, Eisenhower and others in his Cabinet express their fears that European allies would expel U.S. forces should they learn of the ``predelegation.''

Secretary of State John Foster Dulles, certain the information would be leaked to the Europeans, worried that ``foreign governments will take action to curtail (the authorization), whether by eliminating our forces from those countries or subjecting them to civil authority,'' according to a declassified summary of the meeting.

The prospect of sharing authority with the Europeans was anathema to Eisenhower, who spoke of the ``weakness of coalitions'' at the meeting. A memo summarizing a similar meeting Dec. 19, 1958, quotes the president as saying, ``It is most important that word of any delegation from the president be withheld from our allies.''

Still, the memos show that Eisenhower wanted to ensure that commanders understood they should exhaust efforts to contact him and inform the leaders of the countries they were in before carrying out the ``predelegation'' to launch nuclear retaliation.

He instructs Gates to add the clause ``subject to the limitations in accordance with international agreements'' to the instructions to commanders.

A January 1959 revision of the instructions begins by emphasizing the very narrow circumstances under which the commanders could authorize nuclear weapons use.

``Only when the urgency of time and circumstances clearly does not permit a specific decision by the President or other person empowered to act in his stead,'' the instructions say.

Further on, the instructions outline three broad scenarios in which a retaliatory nuclear strike would be justified:

--A submarine or surface craft launches missiles against the United States;

--A Sino-Soviet bloc launch of missiles, bombs, air-to-air attacks or strafing ``against a major U.S. force in international waters or foreign territory.''

--``Sino-Soviet bloc ground, paratroop or other forces make a major assault and thereby effect a significant penetration of an area occupied by major U.S. forces in foreign territory,'' a definition that would have included U.S. forces stationed in Germany at the time.

The George Washington University-affiliated National Security Archive originally applied for declassification of the documents in 1993. Parts of the instructions to the commanders have been blacked out.

Previously declassified documents show that the practice of ``predelegation'' persisted through the Johnson administration. It is not known whether any president subsequently revoked the orders.

On the Net: National Security Archive: http://www.nsarchive.org