King Hussein of Jordan disclosed yesterday that Iraq and Syria, bitter enemies for more than a decade, have agreed through his mediation to have their foreign ministers meet Friday to explore a broad reconciliation and a possible summit meeting between the leaders of the two Arab nations.

Portraying the proposed reconciliation as the cornerstone of promising new efforts to achieve Arab unity in the Arab-Israeli conflict and to help bring an end to the Iranian-Iraqi war closer, the Jordanian monarch said a political truce between Damascus and Baghdad "would enable the Arab world to move from the state of paralysis that has affected us for far too long towards greater cohesion."

Syria has been the only important Arab nation to support Iran in its 5 1/2-year war against Iraq. A shift by Syria toward Iraq would produce a major realignment in Arab politics and possibly in the Persian Gulf war.

During a 40-minute interview here, Hussein also voiced a deeply pessimistic view of Jordanian-U.S. relations in the wake of the Reagan administration's decision to postpone indefinitely the sale of sophisticated U.S. weapons to Amman. He described that decision as bringing to an end "30 years of a very close association" in which the United States has been the major supplier of arms to Jordan.

"We don't know how long this will last, but certainly for the foreseeable future we are reorienting ourselves toward Europe and other sources," he said, noting that Jordan is considering two models of European-manufactured jet fighters, and has recently received new supplies of military equipment from the Soviet Union under an existing contract. He did not provide details.

"We have received the signal loud and clear" from the United States, Hussein observed in tones that alternated between sorrow and bitterness. Speaking of reports that the Reagan administration has decided to supply Stinger antiaircraft missiles to Afghan and Angolan rebel movements after pulling similar missiles out of an arms package for Saudi Arabia, the Jordanian ruler softly added:

"When you take a weapon like the Stinger that is being supplied to many movements in this world which could be described as freedom fighters by some, as terrorists by others, and when you come to governments that have been reliable, that have been your friends and allies for many years, and suggest that you do not wish these weapons to be in their hands, . . . this is very hard to swallow."

The Jordanian ruler, who traveled to the United States to attend the high school graduations of his twin daughters last week, met with President Reagan in the White House on Monday. While he urged the United States to increase its involvement in peace efforts in the Middle East, Hussein held out no hope during the interview of a new American initiative in the near future.

The meeting Friday between the Iraqi and Syrian foreign ministers, which is to take place at the border between the two nations, will be a major diplomatic triumph for Hussein if it occurs. He confirmed that the proposed meeting grows out of visits he made to Baghdad and Damascus and a trip his prime minister, Zaid Rifai, made to Athens to meet with Syrian President Hafez Assad earlier this month.

Assad and Iraqi President Saddam Hussein lead rival factions of the Arab Baath Socialist Party and have accused one another, apparently with justification, of serious attempts to overthrow each other's regimes. Syria's support for Iran in the Persian Gulf war had brought the rivalry to the edge of belligerency in recent years.

But Syrian-Iranian ties have come under open strains in the past three months as Iran shut off shipments of subsidized petroleum and Syria moved to tighten its grip on Shiite Moslem groups in Lebanon that are associated with Iran.

These tensions have surfaced as Jordan and Syria moved to end a decade of estrangement and at times open hostility. Hussein, who has strongly supported Iraq from the beginning of the war, apparently took the initiative in making peace with Assad.

Yesterday, in explaining the Syrian-Iraqi moves toward reconciliation, Hussein laid heavy stress on the effect that non-Arab Iran's occupation of Iraqi territory has had in Syria and the rest of the Arab world. Iranian troops have occupied the peninsula around the Iraqi oil-shipping port of Faw since seizing it in February.

"Syria's leadership and people believe as we do that Arab land is sacred, and must be safeguarded. That is part of the Arab interest and the Arab identity," said Hussein, who lost the West Bank of the Jordan River to Israel in the 1967 war.

Saying that "we have our fingers crossed," Hussein spoke at length of his hopes that the reconciliation of the two feuding Arab countries may "pave the way for a successful Arab summit" that would seek a unified approach toward dealing with Israel.

He left the impression, without saying so explicitly, that an Arab summit conference might be called on to endorse new leadership for the Palestine Liberation Organization, or failing that, to give recognition to new leadership outside the PLO that would cooperate with Hussein in renewed peace efforts.

When asked for his view of the present PLO chairman, Yasser Arafat, Hussein insisted that he would not comment on "internal Palestinian matters." But Hussein did not mask his conviction that Arafat's repeated failures to live up to agreements he had reached with the Jordanian leader to enter American-sponsored talks about peace with Israel had undermined the PLO's claim to legitimacy.

Citing the need for "a leadership that is able to live up to the hopes and aspirations of the people of Palestine," Hussein added later: "Maybe the Palestinians themselves will find it necessary to reorganize themselves in such a way as to enable this [leadership] to emerge."

Jordan, he said, was examining plans to step up its economic involvement in the West Bank and "to look at the needs of the occupied territories."

Syria and Jordan, he indicated, have almost identical views on the need for a United Nations-sponsored international peace conference to work out a Middle East peace settlement, and see eye-to-eye on the leadership problems the Palestinians face.

Syria has bitterly opposed Arafat's claim to lead the PLO and is supporting rival guerrilla movements. Hussein has not gone that far publicly, but his comments yesterday suggested that he is edging toward such a stance.

Asked about the American bombing raid against Libya in retaliation for Libyan support of terrorist acts targeted against Americans, Hussein gave a carefully balanced answer that stressed his opposition in principle to the raid and his opposition in practice to Libya's leader, Col. Muammar Qaddafi.

"Any attack on any part of Arab land we view as an attack on us, and oppose," he said of the American air strike against Libya last April.

But he went on to note that Libya's leader "had sent missiles to Iran that were used to hit an Arab capital, a thing that was [also] shocking to us, that there would be support for an alien force threatening Arab land."