Israeli officials strongly suggested today that Israel will reject a U.N. Security Council resolution authorizing the use of U.N. observers to oversee the fragile cease-fire in Beirut.

While Israel's formal reply to the Security Council resolution awaits a decision by the government of Prime Minister Menachem Begin, an Israeli official today characterized it as an unnecessary distraction from the "main issue" of arranging for the withdrawal of the trapped Palestine Liberation Organization forces in West Beirut.

"We are very, very concerned with the apparent attempt to drag out the negotiations," he said. "The main issue we are in the process of trying to resolve is getting the PLO out of Beirut and Lebanon. All side issues are of lesser importance and when emphasis is given to them it postpones the real issue."

The official added that acceptance of the U.N. resolution would inevitably drag Israel into negotiations over the details of arranging the placement of the U.N. observers in Beirut. "The best and only way to maintain the cease-fire is for the PLO not to interrupt it," he said.

The U.N. resolution, adopted unanimously by the Security Council last night, calls for an immediate cease-fire in Beirut and a "cessation of all military activities within Lebanon and across the Lebanese-Israeli border." It also authorized the deployment of observers to "monitor the situation in and around Beirut" if requested by Lebanon.

Israel appeared to be bending to American pressure today by restraining its military response to Palestinian fire around Beirut. Military officials said that PLO guerrillas opened fire early this morning on Israeli troops in and near the Beirut airport south of the city and that, after holding off for several hours, the Israelis eventually returned the fire.

The announcement noted that the Israeli forces did not employ artillery fire in the exchange, nor were there reports of Israeli air raids or naval shelling such as the massive attack on the Lebanese capital yesterday.

Meanwhile, U.S. Deputy Assistant Secretary of State Morris Draper met with Begin and Foreign Ministry officials. Details of the talks were not made public, but officials said Draper discussed the "mechanics of the negotiations," which to Israel means how to "speed up the negotiations," and reported on the "U.S. knowledge and understanding of where the PLO will go once it leaves Beirut."

Officials declined to say whether Draper brought with him a report on the effort of U.S. special envoy Philip C. Habib to obtain a clear commitment that the PLO is willing to leave Beirut, but they indicated that the Israeli attitude on this point had not changed.

"The PLO has not committed itself to leaving," officials here said again today. "We still don't have the modalities and a timetable for withdrawal. Until this day they still have not come up with a clear, unequivocal commitment to leave Beirut and Lebanon."

Israel also rejected today a World Council of Churches statement published July 28 that condemned the invasion of Lebanon and demanded an Israeli withdrawal.

A Foreign Ministry spokesman said that "while we deeply deplore together with all peace-loving people the loss of life, human suffering and destruction in Lebanon," these developments were the responsibility of "the terrorist organization called the PLO and the Syrian occupation forces."

The spokesman said the World Council of Churches demand "should have been addressed to the PLO."