Jordan's King Hussein said yesterday that recent terrorist acts were "terrible setbacks" to his efforts to win a role for the Palestine Liberation Organization in the Middle East peace process, and he hinted that he has called on PLO Chairman Yasser Arafat to demonstrate the PLO's sincerity about wanting peace.

Hussein, in a satellite interview from Amman on NBC's "Meet the Press," left little doubt that he had made known his anger to Arafat in their meetings last week. But he did not specify whether he was pressing the PLO leader for a public declaration to forswear terrorism.

"We hope to come up with some answers in the very near future," was all Hussein would say about his discussions with Arafat over the damage caused by such incidents as the hijacking of the Italian cruise ship Achille Lauro, the murder of three Israelis in Cyprus and the last-minute aborting of a meeting between British Foreign Secretary Sir Geoffrey Howe and a Jordanian-Palestinian delegation.

"I believe it was our mutual view that some of these actions represented terrible setbacks to the pursuit of peace and that the cause of the Palestinians was adversely affected more than any other," Hussein said.

"We have looked at where we stand right now and it's obvious to me and to him that we have to put our act together once and for all, and we have to know where we stand and where we're going," Hussein added.

"It's obvious that for the PLO to participate in the peace process, which is its right, then they obviously have to determine what actions they have to take to clear that path.

"And I'm expecting some answers soon," he added.

But Hussein declined to be more specific about what he wants Arafat and the PLO to do. Yesterday's interview was the first time the king allowed himself to be questioned publicly about his meetings with Arafat.

The king made clear that despite the efforts of Israeli Prime Minister Shimon Peres and the United States to coax him away from his Feb. 11 agreement to seek peace talks only in association with the PLO, he is not ready to abandon Jordan's partnership with Arafat.

The United States has said that it will have no dealings with the PLO until it pledges to cease terrorism against Israel and accepts United Nations resolutions recognizing Israel's right to exist behind secure borders. Hussein repeated earlier statements that the PLO accepts the principle of "all pertinent U.N. Security Council resolutions." Asked whether the PLO is willing to say that publicly, he added, "As an international conference idea jells and becomes a reality I see such a move by the PLO taking place."

His reference to an international conference was a reaffirmation of his view that peace talks between Jordan and Israel must at least begin in the form of such a conference involving the five permanent members of the U.N. Security Council, including the Soviet Union.

Hussein glossed over questions about whether the Soviet Union should accommodate Israel's refusal to take part in any talks with a country that does not have diplomatic relations with the Jewish state. Asked whether he had discussed these questions with Soviet leaders, Hussein replied, "We haven't had any contact with the Soviet Union. But in the days ahead we expect to discuss it with the Soviets in all its aspects."

Hussein described recent high-level Jordanian meetings with Syria not as a dramatic swing in policy after a long period of strained relations but as part of his continuing effort to "seek the best of relations with the rest of the Arab world."

He noted that the communique concluding the last Jordanian-Syrian meeting had agreed that resolution of the Arab-Israeli conflict requires an international conference, and, when asked if Syria is willing to participate, he said, "I believe this would be the case."

He also expressed anew his anger at the action of Congress two weeks ago in forcing postponement until next March of up to $1.9 billion in U.S. arms sales and making further consideration of the sales contingent on progress toward peace with Israel.

He said that he was awaiting the report of senior military advisers before deciding whether to look elsewhere for arms.