Israeli Prime Minister Menachem Begin, beginning critical talks with President Carter last night on the Middle East peace process, said the Egyptian-Israeli negotiations are in "deep crisis" and bluntly warned Carter, "We cannot be pressed into signing a sham Document."

Within moments of his arrival here, Begin, to the Obvious dismay of his hosts, brushed aside U.S. pleas that the treaty disputes not be discussed in public and lashed out in extraordinarily tough language at rhe Egyptian negotiating posistion.

He also made unmistakably clear his view that the Carter administration has tilted toward Egypt and is pressuring him to sign a treaty that Israel considers contrary to the agreements reached at the Camp David summit last September.

"It is my duty to state the fact that the negotiations between Egypt and Israel reached the stage of deep crisis because we have been asked lately to sign documents attached to the peace treaty contradictory to the Camp David agreements," he charged in his Andrews Air Force Base arrival statement.

"These documents would make it possible for our sovereign neighbor [Egypt] at any moment to declare the treaty null and void or to make war against Israel," Begin added. "Under such circumstances, it would not be a peace treaty."

His defiant words seemed to offer little comfort for U.S. officials hoping that Begin's visit will lead to a new Camp David summit at which the long-delayed treaty can be turned into a reality.

Israel rejected Carter's latest summit invitation because Egyptian President Anwar Sadat would be represented by a deputy and because Israel contends that the United States has sided with Egypths position.

Begin did agree to private talks with Carter in an attempt to regain the momentum toward a summit. But, despite U.S. efforts to keep the bargaining disagreements behind closed doors, Begin appeared to be trying to counter alleged U.S. official pressure by taking his case directly to the American people.

When Carter greeted him at the White House, Begin, in an unmistakable reference to the turmoil in Iran, implied that Israel is the last dependable American ally in the Middle East.

"The free world is in danger," Begin said. "Israel has now proved it is the only stable ally of the United States and of the free world because we have the inherent stability of democracy...."

The only thing in Begin's statements to rouse any hope of optimism among U.S. officials was his promise to "make any effort possible during the coming days to try and overcome these difficulties."

Whether that can be done will depend on Carter's ability to convince Begin that the United States is not applying strong-arm tactics to Israel and that the proposals put forward by the administration in hopes of breaking the impasse are in the interest of both Israel and Egypt.

To that end, Carter prefaced their two-hour meeting last night by saying he was "very proud" to be conferring with the Israeli leader and added: "We're determined to succeed. We will be tenacious in our effort."

After the meeting, a brief statement was issued saying the talks were conducted "in a most friendly atmosphere" and describing tham as "a useful prelude" to the coming discussions.

Speaking with reporters before he entered the Blair House official guest residence, Begin described the session as "one of the most important and constructive talks I ever had with the president." Begin said "there was not even one difficult moment."

Perhaps the surest sign of the extraordinary importance that Carter attaches to the talks was announcement of the schedule for today. The two leaders will meet at 10 a.m. and Begin will have a working lunch with Secretary of State Cyrus R. Vance. He and Carter will confer again this afternoon, and this evening Begin will be carter's host at a Jewish Sabbath evening dinner in Blair House.

But, despite U.S. insistence that Carter wants "to go the second mile" in bringin the two Middle East adversaries together, the most recent proposals advandced by the United States are known to conform more closely to Egyptian rather than Israeli desires.

The most important disagreement involves Egypt's insistence that the treaty be accompanied by a letter setting forth a target date for completing separate negotiations on establishing Palestinian autonomy in the Israeli-occupied West Bank and Gaza Strip. The United States is understood to be recommending that Israel, through an exchange of letters between Begin and Sadat, agree to a one-year target timetable for completing the autonomy talks.

The administration also is believed to have backed an Egyptian demand for scrapping aprovision in the draft treaty text that would give the agreement priority over Egypt's mutual defense kpacts with other Arab states that might come into conflict with Israel.

The United States, in addition, has sided with Sadat's reluctance to station an ambassador in Israel until Israeli withdrawal from the Sinai is completed and progress is made toward Palestinian autonomy in either Gaza or the West Bank.

Another disputed point centers on Egypt's desire to have language in the treaty allowing it to be reopened for possible revision five years after it is signed. As a compromise, the United States has suggested dropping the five year provision and adopting a formula providing for a review whenever either party requests one.