President Anwar Sadat yesterday for the first time appeared prepared for the first time to accept the possible failure of his floundering Middle East peace initiative and hinted a major reassessment of Egyptian foreign policy could come within months.

"Either the peace process regains momentum" in the two months ahead, he told a news conference at his guest house by the Nile outside Cairo, "or proves to be a failure."

[In Tel Aviv, Israeli government officials rejected Sadat's deadline, calling the announcement of it a "very grave" development and saying, "It is impossible to set a time frame for such intricate negotiations," UPI reported.]

Adding to the sense of pessimism, relieved only by the "good omen" of congressional approval for warplanes for Egypt, was Sadat's admission that the United States had "not yet" agreed to become "a full partner in the peace process.

"I am waiting for the moment when the United States will take full share as a full partner to give full momentum" to the negotiations, he said.

A major thrust of his remarks was to reprimand to the foreign press in tones of injured innocence for reflecting criticism of his current crackdown on domestic dissent.

Running through his remakrs was the leitmotiv of change in the foreign press which in six months has ceased echoing his peace initiative and become a sounding board for the opposition he seeks to discredit.

Sucking on a pipe, mopping his brow in the summer heat and waving a stack of translated newspaper clippings, Sadat said, "I am not happy with what I read in your papers."

Sadat refuted suggestions that his domestic crackdown on some jouranlists, dissidents and politicians is linked to what he called the "stalemate" in the peace negotiations with Israel.

Even the "complete failure" of his peace initiative, he said, "will not be the end of the world."

At one point he said the "momentum of the peace process was slackening," at another he described it as frozen. "But it has not stopped."

As for Israel, he said, "we are ready, openheated and openminded, for the establishment of peace and good neighborliness and the security of Israel," he said. "But we are not ready to surrender any part of our land."

So far, he said, Israel had not been forthcoming, but any new element from Israel would be met with "reciprocity."

Asked about the possibility of a summit to end the splits in the Arab world caused by his go-it-alone peace policy, Sadat said such a meeting might be possible within two months.

"In those two months we shall reach results," he said. Either the peace process regains momentum again or proves to be a failure."

He also promised a "surprise" - possibly a policy reassessment - for the July 23 anniversary of the revolution which overthrow the Egyptian monarchy in 1952.

At the same time however, he said the "big test" would come in October with the expiration of the U.N. Emergency Force mandate set up almost three years ago in Egyptian-Israeli negotiations masterminded by then-Secretary of State Henry Kissinger.

What would he do if the peace initiative had not borne fruit by then" He said he would cross that bridge when he came to it and added, "I am not worrying about the next six months."

In criticizing the foreign press, Sadat declared, "You are supposed to be the link between us and the people there, in Europe, Great Britain and America." But, he suggested, Cairo-based foreign correspondents are unduly influenced by the Egyptian opposition such as columnist Mohammed Hassanein Heikal and leftist writer Mohammed Sid Ahmed.

The crackdown affects some 150 Egyptians who are specifically under investigation for defaming Egypt.

Sadat claimed such dissidents were behind previous criticism of his government - before the October, 1973 war against Israel; at the time of the January, 1977 Cairo food riots; before his peace initiative last November and again now.

In an oblique allusion to a recent Heikal interview on the BBC Sadat reminded the correspondents of the fate of Williams Joyce, called "Lor Harvhaw," a turncoat Englishman who broadcast for the Germans during World War II.

"The British sentenced him to death for directing propaganda against his own country," Sadat said. As fro Mohamed Sid Ahmed, Sadat said in a tone of voice approaching a scream: "This precise man has abused his country in Italy where the writer had been invited this week to receive a prize for a recent book."

Although Sadat singled out the BBC, the Times of London, Time magazine and the Manchester Guardian fro past and present reporting, he told his audience," I will not take any measures against you."

Only this morning, however, an editorial in the government-controlled newspaper Al Akhbar said, "If the BBC correspondent in Cairo thinks the guarantees of feedom of the press means joining the (opposition) slander campaign, he must understand that respecting this freedom is a condition to stay among us."

Sadat stressed that in his nearly eight years in power he had closed concentration camps, dismantled censorship, allowed the foreign press to travel and generally made Egypt into one of the freest countries in the Middle East.

Egypt was pledged, he said, to the multiparty democratic system. But he again denounced Marxists, latter day Nasserites and politicians from the pre-1952 revolutionary period as "wrecks" that would continue to be removed when they get in Egypt's way."

Sadat blamed himself for having authorized Marxists to "to control the leftwing in our democracy," an allusion to his decision to allow three political parties to replace the previously monolithic Arab Socialist Union.