After an interruption of almost two years, Israel and Egypt resumed negotiations today over a small but economically important strip of land on the Gulf of Aqaba that has been a major source of friction since the signing of the 1979 Egyptian-Israeli peace treaty.

The delegations were joined by three U.S. officials at a U-shaped negotiating table, meeting for two hours at the Desert Inn hotel in this city in the Negev Desert. The talks, which are scheduled to continue on Monday and Tuesday, center on a four-acre strip of land at Taba, immediately south of the Israeli city of Elat. Taba is controlled by Israel but is claimed by both countries and has been in dispute since the peace treaty was signed.

After the opening session, which lasted one hour less than scheduled, an Israeli official said the discussion had been conducted "in a good spirit," as both sides reiterated longstanding positions but pledged to bring "new ideas" Monday.

Although the Beersheba negotiations focus on a narrow issue, involving interim security arrangements in Taba before the overall dispute is settled, the fact that the two sides were talking again was interpreted as a hopeful sign. Israeli Prime Minister Shimon Peres, who has made no secret of his desire to hold a summit conference with Egyptian President Hosni Mubarak, has indicated his eagerness to settle the Taba dispute as a necessary condition for improved ties.

Zvi Kedar, the head of the Israeli delegation, said in his opening statement that Israel hoped the negotiations marked "a fresh beginning of a broader dialogue for the strengthening of our relations." Outside, demonstrators held a sign that said, "Don't give up little Taba for a false peace trap."

Egypt's willingness to resume talks has been linked by Israeli officials to Mubarak's scheduled meeting with President Reagan in Washington in March. According to this interpretation, Mubarak calculated that signs of softening in Egypt's relations with Israel will improve his chances of winning a $1 billion increase in U.S. aid.

Israel hopes to confine the Beersheba talks to the narrow issue of defining security arrangements. An interim agreement was reached April 25, 1982, just prior to the final Israeli withdrawal from the Sinai Peninsula. The two sides agreed that the Multinational Force and Observers, which is stationed in the Sinai to monitor compliance with the peace treaty, would enter the disputed border points until the differences were settled. But the sides disputed the role of the force, and it was not deployed.

Israel has said it does not object to the force entering Taba as observers but wants police and security services to remain in the hands of Israeli Border Police, whose presence in the territory serves as a concrete sign of Israel's claim to sovereignty there.

Egypt maintains that the multinational force should take over security duties in Taba and that the Israeli Border Police should leave. In his opening statement, Abdel Halim Badawi, the head of the Egyptian delegation, said, "Any official presence of a police force in the area is not according to the spirit and letter of the April 25, 1982, agreement."

According to Israeli officials, Badawi also reiterated Egypt's claim to sovereignty over Taba, and Kedar replied that these talks concern only the interim role of the force in the territory.

Taba is one of 15 disputed points along the border unsettled by the peace treaty. It is the largest and the only one of any economic significance. The strip of sandy beach at the northeastern tip of the Red Sea is the site of an Israeli-owned, $35 million luxury hotel that opened after the peace treaty was signed.

For the Egyptians, Taba has become an issue of national honor. Mubarak has made resolution of the dispute one of three conditions for an improvement in Egyptian-Israeli relations and the return of Egypt's ambassador to Tel Aviv. The other two are an Israeli withdrawal from Lebanon and progress on the Palestinian problem in the Israeli-occupied West Bank and Gaza Strip.

Egypt recalled its ambassador from Tel Aviv in 1982 to protest the massacre of Palestinian refugees at the Sabra and Shatila refugee camps in west Beirut.

Under the terms of the 1982 agreement, border disputes such as the one at Taba are to be settled by negotiation, conciliation and, if the first two steps fail, binding arbitration. The Egyptians have called for arbitration of the Taba dispute.

Earlier negotiations made no progress as the overall tone of Egyptian-Israeli relations has remained cool.