Israeli Defense Minister Ariel Sharon said today that Israel "cannot show any flexibility in the future" because of attitudes in Europe and the United States toward the Middle East peace process.

Echoing a tough posture adopted in public statements in the last 24 hours by Prime Minister Menachem Begin and Foreign Minister Yitzhak Shamir, Sharon said, "When it comes to our existence, Israel cannot show any flexibility whatsoever. We decided to live."

In his first press conference since assuming the second-highest post in Begin's Cabinet, Sharon said, "I think Israel has made tremendous concessions until now. But the voices we hear from Washington and Europe do not encourage us."

Sharon's comments, coupled with similar statements made by Begin and Shamir just three days before the resumption of ministerial autonomy talks in Cairo on Thursday, appeared part of a coordinated campaign in the government to signal Israel's exasperation and unwillingness to be pressured by alternative peace initiatives.

All three ministers referred specifically to the European Common Market's Middle East peace initiative and the eight-point peace plan advanced by Saudi Arabia's Crown Prince Fahd.

Begin said today that Israel had reached the "absolute limits" of its concessions, having given up its strategic positions in the Sinai Peninsula and pledged to dismantle Jewish civilian settlements there.

Shamir, in a speech to a Jewish fund-raising group last night, said, "We have reached, even passed, the limits of our concessions both in the south Sinai and in our proposal for full autonomy for the Arab inhabitants of Judea and Samaria the West Bank . The reaction of the West and its present attitude to the oil-producing states may cause us to reassess our attitude. We cannot afford to continue taking risks that are met only with demands for more risks."