Secretary of State George P. Shultz today characterized apparent Soviet concessions in the long-stalled European security talks in Madrid as "a positive development" in East-West relations but said much more progress would be needed to provide the basis for a U.S.-Soviet summit meeting.

Speaking to reporters aboard his plane en route to Pakistan after a three-day visit to India, Shultz carefully qualified his statements because it was uncertain from reports in hand whether Moscow conclusively has accepted the entire compromise package, proposed by Spain, that had previously been accepted by the West.

If this is the case, Shultz said, Moscow's stand "provides the basis for an agreement and a conclusion to the Madrid discussions."

Nonetheless, he added, "I think it's a long leap from there to a summit meeting."

Reminded that he has been saying in congressional testimony and press conferences that specific, positive accomplishments in negotiations would be required for a meeting between President Reagan and Soviet President Yuri Andropov, Shultz responded, "There are lots of other issues beyond the Madrid talks and other things that are part of an overall picture that we'll want to talk about and evaluate." Asked if all negotiations have to move to justify a summit, he replied, "No. But I don't think one agreement--something of this kind--suddenly changes everything. It is an incremental movement of significance."

The Soviet announcement, which came as West German Chancellor Helmut Kohl prepared to visit Andropov in Moscow, was interpreted by some officials in the Shultz party as another Soviet move aimed at the political struggle in Western Europe over scheduled U.S. missile deployments there late this year.

Officials in the Shultz party said it was too early to assess the impact or importance of these moves as a whole, but added that it seems clear that Moscow has decided to introduce a greater degree of tactical flexibility in its diplomacy, at least.

Still another set of negotiations involving the Soviets--the U.N.-sponsored talks on the future of Afghanistan--was the central subject today of Shultz's meeting with Pakistani Foreign Minister Sahabzada Yakub Khan, who is a key participant.

According to a senior U.S. official who participated in today's meeting, Yakub Khan told Shultz that "some progress had been made" in the 10 days of Geneva discussions completed just a week ago, but that "many key issues have not been addressed or resolved."

The official, who briefed reporters on condition that he not be quoted by name, said the progress appeared to be more in atmosphere than in specifics. The basic Soviet position, he said, remains that its troops are in Afghanistan in response to a request from the legitimate government to assist in dealing with an externally promoted insurgency and that its troops will go home when the emergency is over.

Pakistani sources said their country's emphasis in the recent round of U.N.-sponsored talks was to request a specific timetable for the withdrawal of Soviet forces. The Pakistani plan is that a cutoff of outside aid to Afghan rebels and the phased return of Afghan refugees would take place at the same time as the Soviet withdrawal.

Shultz has repeatedly denied during this trip that the United States is lukewarm to a political settlement of the Afghan question, and disclosed in New Delhi yesterday that he had written Soviet Foreign Minister Andrei Gromyko to deliver the same message.