BONN, FEB. 9 -- Jordan's King Hussein said today that both Israel and the United States were responsible for the past failure of Middle East peace initiatives, and warned that he is "losing all hope" for a solution to the Palestinian problem unless a major international effort is made.

The current unrest in the West Bank and Gaza Strip, and the harsh Israeli tactics used to quell it, are a "watershed, a historic event" that he hopes will "shake the world out of its complacency," Hussein said.

He said that he welcomed new U.S. engagement in the Middle East. But he made clear his belief that any attempt to arrive at "piecemeal" solutions short of eventual Israel withdrawal from the occupied areas will be doomed to failure.

"We welcome the concern, we welcome the interest, and we welcome what appears to be a concerted effort to engage" all parties involved in the situation, Hussein said in an address here to a West German foreign policy group. "We are hopeful that it is leading to something constructive. But we do not have the full picture yet, so I cannot comment."

U.S. Middle East envoy Richard W. Murphy is traveling through the region to consult on a peace plan that would grant limited Palestinian autonomy in the West Bank and Gaza Strip. This would be followed by negotiations, the outline of which has not been made public, over a more permanent resolution of the Arab-Israeli dispute.

Most of the world, Hussein said, favors an international peace conference involving the United States, the Soviet Union and other major powers as well as regional governments and the Palestine Liberation Organization, as the best way of guaranteeing a lasting solution. At a meeting yesterday with European Community foreign ministers, Hussein asked for and received a reaffirmation of their support for such a conference.

"One-half of the political spectrum in Israel itself" also supports it, Hussein said, in a reference to the Israeli Labor Party, led by Foreign Minister Shimon Peres.

"The United States continues to oppose it until it secures the approval of" Israeli Prime Minister Yitzak Shamir, he said. "Israel must bear the responsibility for the faltering peace process, and those who are in a position to influence the Israeli position, yet fail to do so, must share the blame."

"We are still hopeful that the United States will assume responsibilites as a superpower and reconsider its position," he said.

The wave of violence that began in the occupied territories two months ago has captured international attention and Hussein appears eager to capitalize on this.

While the new urgency has given impetus to the search for peace, however, "the truth is that the time factor has made the problem far more intense," he said. "Time has bred a generation of Palestinians who see Israel as nothing more than a ruthless occupier."

Israel, he said, has "exploited the time factor to its own advantage" by moving the Arab-Israeli conflict into the U.S. political process at a moment when America is "subject to electoral consideration."

Hussein also reiterated Arab insistence that the Palestine Liberation Organization must be an active party to make any negotiations worthwhile. Both the United States and Israel have rejected any PLO participation.