The abrupt suspension of the Egyptian-Israeli negotiations on Palestinian autonomy has left the Israeli government perplexed and fearful that Egyptian President Anwar Sadat may be attempting to exert 11th-hour pressure on the United States to force Israel into concessions it is not prepared to make.

Amid a flurry of anxious speculation on Sadat's motives in calling off next week's scheduled autonomy talks in Cairo, Israeli officials involved in the negotiations professed tonight not to know whether the decision represents a tactical ploy by Sadat or whether it could lead to a serious disruption in the Middle East peace process.

The only thing that is clear, the officals said, is that the negotiating holdup originated with Sadat himself, and not the Egyptian negotiating team headed by Prime Minister Mustapha Khalil, which left Tel Aviv Wednesday anticipating another round of bargaining in Cario on Monday.

In Cairo, Khalil said Egypt's decision was taken "due to the lack of progress" in the talks. He cited a staement Tuesday by Prime Minister Menachem Begin in which he reiterated Israel's intention to retain permanent control of security in the occupied territories.

Tonight, the spokesman for Israel's neogtiating team, Dan Pattir, said that "after the meetings in Herzliya (near Tel Aviv), it was clear that they wanted us to go to Cairo and sit from Monday to Friday. What made Sadat change his mind is a mystery," he added. "I think the decision was a surprise to all three sides -- Israel, the United States and the Egyptian delegation, except Sadat."

Pattir said Israel has not been formally notified by Egypt of the bargaining suspension, and that its interpretation of the decision has been hindered by a lack of information. Sadat said yesterday the ministerial-level negotiations on the proposed autonomy for the West Bank and Gaza Strip should be suspended, and today he announced that the technical-level working groups also would not convene Monday as scheduled.

Interior Minister Yosef Burg, head of the Israeli delegation, said last night there was no point in convening the sub-ministerial working groups if the ministers are not working in concert and making on-the-spot political decisions.

The question of responsiblity for security in the occupied territories during a five-year transition period after an autonomy agreement has emerged as a major stumbling block. Israel wants to retain full military control over the West Bank and Gaza, while Egypt envisions a joint Egyptian-Israeli security presence in Gaza and an Israeli-Jordanian force in the West Bank.

Israeli sources close to the negotiations said Sadat's suspension of the talks could be an attempt to exert more pressure on Israel to yield on the security issue. If that is the case, Israeli officials said, it represents a serious development in the peace process.

A less ominous motive, the Israeli said, would be an attempt by Sadat to postpone any decisions until the eve of May 26, the target date for agreement, and then propose a face-saving extension and open-minded talks.

Burg today said that "now the world can know who stopped or postponed those negotiations."

But he said Israel's resolve on security is firm. "Our security is our life. We came here in order to live . . . Nobody of good senses in this world would understand if we go easy on the question of security."

Israeli officials taking pains not to exacerbate the situation by condemning Sadat's decision.