Attempting to resolve sharp disagreement within the Reagan administration, Secretary of State George P. Shultz announced yesterday that the United States will continue to limit testing and development in its "Star Wars" space defense program according to "a restrictive interpretation" of the 1972 Antiballistic Missile Treaty, even though it has decided that "a broader interpretation of our authority is fully justified."

Shultz's statement followed criticism within the Atlantic alliance and in Congress that the administration's recent reinterpretation of the ABM treaty would gut the pact 13 years after it was signed. Shultz said yesterday that President Reagan "has chosen to take a narrower interpretation" of the treaty than the administration now thinks is legally required. Shultz spoke yesterday at a meeting of NATO parliamentarians in San Francisco. He told lawmakers shortly before his address that President Reagan made his decision on Strategic Defense Initiative testing and the ABM treaty after a meeting of his senior advisers last Friday. This followed the first public indication the previous Sunday, by White House national security affairs adviser Robert C. McFarlane on NBC News' "Meet the Press," that the administration was reversing the position taken by U.S. administrations since 1972 on what is permissible under the U.S.-Soviet treaty.

Under the "broader" legal interpretation, the ABM treaty would not impose any limitation on "testing" or "development" of space-based antimissile systems of an exotic nature such as that pursued under the SDI. This interpretation is based on an ambiguously worded "agreed statement" appended to the ABM treaty which says that if new antimissile weapons "based on other physical principles" are created, limitations on them would be subject to further discussions between the superpowers.

Those administration officials arguing for the broad interpretation of the treaty say that the agreed statement leaves room for testing and development of exotic weapons. Others, including former officials who negotiated the ABM treaty in the Nixon administration, say the key provision is Article V of the treaty itself, which explicitly outlaws testing and development of "ABM systems or components" based at sea, in the air and in space, which would cover most aspects of the SDI program.

With yesterday's announcement, an official said, the administration is now respecting some of the most important restrictions of the ABM treaty as a matter of presidential policy rather than a matter of law. Thus Reagan's decision represented a partial turning back from the 180-degree reversal on SDI-related requirements of the ABM treaty that had been announced only the week before.

Shultz did not say how long the U.S. self-imposed restraints on its SDI research and testing program would continue but spoke of a "commitment to pursue the program as currently structured."

Officials said that for the foreseeable future, the SDI program will go forward as outlined to Congress in a report last April. That report said testing of exotic components of future missile defense systems would be legal if the components tested were modified so they could not be used in an antimissile system as tested. That rationale has also been criticized by arms control advocates as one the United States would never accept if the Soviet Union invoked it to justify Soviet tests on exotic weaponry.

Chairman Dante B. Fascell (D-Fla.) of the House Foreign Affairs Committee, who sharply criticized the administration's "broad" legal reinterpretation of the ABM treaty last week, said Shultz's announcement "is a very welcome and constructive step." Fascell, who was among the NATO legislators whom Shultz addressed, said the announcement "should eliminate a great many of the concerns expressed by our allies" about U.S. policy on the treaty.

Because of "ambiguities" that still remain, Fascell said, the committee will go ahead with hearings to explore the administration posture on the ABM treaty.

Rep. Norman D. Dicks (D-Wash.), another member of the U.S. delegation at San Francisco, said Shultz's statement raises many questions. "Just what is the restrictive interpretation that the U.S. is going to abide by? Does the administration now believe that the Soviets could go ahead with testing and development without violating the treaty?"

"I support what the president did but it would be far wiser to stick to the restrictive interpretation" as a matter of legal doctrine, Dicks said.

McFarlane's statement on "Meet the Press" was a surprise to senior policy-makers, who said a high-level meeting to discuss a revised legal interpretation of the ABM treaty had been concluded without any agreement or final decision.

McFarlane's statement led to several days of intense debate inside the administration as well as among U.S. allies and members of Congress, culminating in the Friday session at the White House. There was general agreement, sources said, that the legal interpretation of the treaty announced by McFarlane should be accepted -- to do otherwise would have been to repudiate him -- but there was disagreement about what the U.S. practical posture toward the treaty restrictions should be.

Reagan's decision on the matter was tightly held. As late as Saturday a Pentagon official deeply involved in the arms negotiations said he would be "astonished" if Reagan would accept limitations on SDI more restrictive than the "broader" legal interpretation, which originated with a Defense Department lawyer. Yesterday the same official said it was not clear to him that his side had lost the argument, pointing to the fact that Shultz did not say in the announcement how long the administration will continue to abide by the "restrictive interpretation" of the treaty.

Shultz acknowledged in his speech that the treaty and documents surrounding it "are subject to differing interpretations." The administration came to its conclusion after "a careful analysis of the treaty text and negotiating record," he said, adding that "this is, however, a moot point," since Reagan has reaffirmed that SDI testing "will continue to be conducted in accordance with a restrictive interpretation of the treaty's obligations."Picture, Secretary of State George P. Shultz: the ABM treaty and its documents "are subject to differing interpretations, UNITED PRESS INTERNATIONAL