In back-to-back interviews with Egyptian and Israeli journalists, President Carter has reiterated basic U.S. policy toward recognition of the Palestine Liberation Organization, but with a subtle shading of tone tailored to his two distinct audiences.

Responding to questions from an Isaeli television interviewer, the presidnet strongly restated longstlanding U.S. policy, which calls in the PLO to accept a United Nations resolution recognizing Israel's right to exist before the United States will deal with the organization.

"Until the PLO is willing to do these things, we will not deal with the PLO," Carter told the Israeli audience.

A few minutes later, during an interview with an Egyptian journalist, the persident repeated the same conditions for U.S. recognition of the PLO but stressed that the United States is anxious "to have direct relations with the Palestinians," including the PLO.

"And as soon as the PLO itself as an organization is willing to acdept these bases, then we will immediately start working directly with that organization as such."

The interviews were conducted Thursday and made public eysterday by the White House following their broadcast on Egyptain and Israeli television.

Carter clearly chose his words carefully in discussing the Palestinians, whose future is the key element in the Middle East peace negotiations that will continue after the signing of a peace treaty between Israel and Egypt at the White House Monday.

Yesterday, Isreli Foreigh Minister Moshe Dayan met Twice with Secretary of State Cyrus R. Vance at the State Department to discuss "memorandum of agreement" between the United States and Isreal in connection with the Egyptian-Isreali peace treaty. One key question in the Vance-Dayan talks was the extant to which the memorandum would explicitly restate that the United States will not recognizer or negotiate with the PLO until the PLO recognizes Israel's right to exist.

Emergin from the second meeting, Dayuan said, "We are not thourgh yet. I do hope that tomorrow morning we will reach final agreement. On basics, we dco agree between us. The only question is how to word it. It's a matter of language."

Vance also met yesterday with Egyptian Defense Minister Kamal Hassan Ali, and last night with Isreaeli Defense Minister Ezer Weizman.

Weizman discussed with Vance the final details of the peace treaty involving the timing of Israeli with-drawal from oil fields in the Sinal.k

One month after the treaty signing, set for 2 p.m. Monday on the front lawn of the White House, Egypt and Israeli will begin negotiations on establishing local autonomy for Palestinians living in the Israeli-occupied territories of the West Bank and the Gaza Strip. Arasb leaders have denounced Egyptian President Anwar Sadat for agreeing to a peace treaty with Isreal, accusing him of abandoning the Palestinians.

The Israeli attitude toward the PLO, which has sworn to destroy Israel, was summed up by Israeli Prime Minister Menachem Beign, who arrived yesterday in New York. Asked about PLO Chairman Yasser Arafat's threat to undo the treaty, Begin said, "The PLO is the most barbaric organization since the Nazis. Their barbaric attacks will be dealt with."

In other developments involving the Middle East:

The United Nations Security Council, after two weeks of often bitter debate, ordered an investigation of the continued movement of Israeli settlers into occupied Arab teritories. Israel immediately announced it would not allow a U.N. commission into the occupied lands. The United States abstained in the 12-to-0 Security Council vote.

Israeli Agriculture Ministry officials announced that Israel will shortly establish four new settlements in the West Bank territory.

Syrian Foregin Minister Abdel-Halim Khaddam predicted that the peace treaty to be singed Monday would lead to the downfall of egyptain President Sadat, and that Arab states would impose a boycott against Egypt as soon as the treaty is signed.

Egyptain officials announced that Sadat would skip a planned European stop enroute to the United Statres and woll arrive in Washington tonight, a day ahead of schedule.

In the interview on Israeli television, Carter predicted that Arab attempts to undermine the peace treaty would be brief and unsuccessful.

"Obviously, there is going to be a period of time within which the PLO and some of the Arab countries will threaten increased violence or economic punishment, terrorism, instability," he said. "I really believe that period is going to be relatively brief," he said, adding that there is "a very good possibility" that other Arab nations will eventually join the peace negotiations.