Soviet leader Mikhail Gorbachev said today that a U.S.-Soviet summit meeting could go ahead this year despite the recent rise in East-West tension, but warned that if the Reagan administration continues its present course, "a shadow will be thrown over all plans for a future summit."

In his first direct statement on prospects for a meeting with President Reagan since the U.S. raid on Libya last Tuesday, Gorbachev said a summit meeting would take place if the United States agrees "it is necessary to take this path." The Soviet Union, he added, is "ready to take realistic steps along the path to peace."

However, referring to the Libya bombing and recent U.S. nuclear tests, Gorbachev said that if the Americans "continue to act as they do today, if they continue to make the international situation explosive and to drive away the spirit of Geneva, then I think a shadow will be thrown over all plans for a future summit. That should be thought over in Washington."

Gorbachev said that "if a new summit is to be organized, then there must be an atmosphere in international relations that allows for real hopes that the summit will be a step forward." He added that "from our side, we are ready for a new series of steps."

Responding to Gorbachev's comments, the White House said yesterday that it assumed this year's summit would occur as planned and that it was ready to discuss a wide range of issues with Moscow, including terrorism.

[The White House statement said a summit this year in the United States was in the best interest of both countries.]

Gorbachev, on his first visit to East Germany since taking power last year, has been attending the congress of the ruling Socialist Unity Party here.

The Soviet leader's remarks came in response to a journalist's question during a tour by the Soviet delegation today of the Cecilienhof Palace in Potsdam, where the Potsdam Conference on the future of Europe was held by Allied leaders in August 1945. Gorbachev's remarks were reported later in German by the official East German news agency ADN.

Gorbachev's statement expanded on a speech he delivered to the East German communist congress on Friday that also suggested a willingness to advance U.S.-Soviet talks despite what he described as a general trend of "militaristic and aggressive U.S. actions." Gorbachev said then that all of Moscow's arms proposals are "still valid" and offered what he called "a new initiative" on the reduction of conventional military forces in Europe.

The Soviet leader has made no public reference here to Moscow's announcement last Tuesday that it had canceled a planned meeting between U.S. Secretary of State George P. Shultz and Soviet Foreign Minister Eduard Shevardnadze in response to the raid on Libya. After the attack, the Soviets called the meeting, scheduled for May 14 to 16, "impossible at this stage." Shevardnadze had planned to visit Washington to arrange a meeting between Reagan and Gorbachev in the United States later this year.

Reagan and Gorbachev agreed at their first meeting in Geneva last November to hold summit talks this year and in 1987. Since then, the Soviets have delayed setting a date for the meeting and Gorbachev has appeared several times to link the scheduling of the summit to progress in arms control negotiations.

Gorbachev also has proposed meeting Reagan in a European capital to conclude a treaty banning nuclear testing, an offer rejected by Washington. His statement did not make clear whether he remained open to a summit meeting in the United States that was not linked to the arms talks.

On Thursday, East German communist leader Erich Honecker delivered a speech endorsing the idea of a U.S.-Soviet summit for banning nuclear testing, and, as Gorbachev looked on, did not mention the Geneva agreement for summit talks.

Gorbachev said he hoped the Reagan administration would study his recent arms control proposals, and cited his statement on conventional force reduction Friday as an example of the "new steps" Moscow was willing to take.

His vaguely worded description of the initiative called for a reduction of troops and tactical aircraft in NATO and Warsaw Pact forces, and said verification of an agreement could include on-site inspection.

Western diplomats here describe the offer as similar to previous Soviet positions in the long-stalled East-West negotiations in Vienna on conventional military forces. Gorbachev mentioned the initiative as part of an appeal to West European opinion, a principal target of his statements here.

Gorbachev's prepared remarks at Potsdam were devoted to praising the agreements made there and at Yalta by Allied leaders. He said they had created "the possibility of a development of free and democratic states in Europe" as well as 40 years of peace.

He added that the danger of war still existed because "militaristic circles" in the West believed they could establish military superiority over the Soviet Union and thus dictate international events.