Behind a tight veil of secrecy, senior representatives of the United States and Soviet Union opened two days of discussions here today on a range of issues related to the Middle East.

It was the first time in more than seven years that Moscow and Washington had held policy-level consultations on the Arab-Israeli dispute. This time Afghanistan and the Persian Gulf also are on the agenda.

The timing of the meeting stirred speculation about possible new peace moves following last week's visit to Washington by Saudi Arabia's King Fahd and reports that Jordan was now prepared to act on behalf of the Palestine Liberation Organization in peace negotiations.

The U.S. delegation, headed by Richard Murphy, assistant secretary of state for Near Eastern and South Asian affairs, included a member of the National Security Council and a diplomat from the U.S. Embassy in Moscow. They met for more than five hours at the Soviet Embassy with a delegation led by Vladimir Polyakov, head of the Near East division of the Foreign Ministry. Talks are to conclude Wednesday at the U.S. Embassy.

Upon leaving the Soviet compound, Murphy refused to discuss the talks other than to say they were "interesting." U.S. Embassy officials said no joint statement would be released. Administration officials have insisted that no breakthrough should be anticipated.

In Jerusalem, an official said Israel welcomed resumption of the superpower dialogue but he made clear that the Soviet Union could not hope to serve as a mediator in the area until it establishes diplomatic relations with Israel, The Associated Press reported.

Saudi state radio commended what it described as "a positive retreat" in the U.S. attitude, which it said had until now insisted on barring the Soviets from the peacemaking process, Deutsche Presse-Agentur reported.

The last high-level U.S.-Soviet talks on the Middle East were in October 1977, between then secretary of state Cyrus R. Vance and Foreign Minister Andrei Gromyko.