Top Israeli officials appeared divided today on the prospects of an American-negotiated plan to evacuate trapped Palestinian guerrillas from West Beirut.

Defense Minister Ariel Sharon insisted that no agreement has been reached on a withdrawal of the guerrillas from the besieged Lebanese capital.

After meeting with U.S. special envoy Philip C. Habib outside Beirut, Sharon told Israeli radio, "There is no agreement since the Arabs don't want the terrorists. In any event, the terrorists are going to have to leave Lebanon one way or the other."

In contrast, Prime Minister Menachem Begin and other top Israeli officials in Jerusalem reportedly were encouraged by a letter received from Secretary of State George P. Shultz assuring them that the United States believes final agreement on a satisfactory withdrawal plan is near completion, Washington Post correspondent Edward Walsh reported.

If Shultz's assessment "is based on facts and if the problems that remained can be solved, we might be close to solving the situation in a diplomatic way," said a senior official after a meeting of the Israeli Cabinet.

Israeli Army radio reported that Begin, in a speech at the nation's military academy, expressed optimism that the guerrillas "will leave soon, and we will not have to enter West Beirut."

In his reply to Shultz, Begin said that Israel will not insist that all Palestinian guerrillas leave the Lebanese capital before a proposed multinational peace-keeping force arrives, the radio said. But Begin added that Israel does want more than half of the fighters evacuated first.

Today marked the second straight day of relative peace in the battered city despite intermittent artillery exchanges between Israeli and Palestine Liberation Organization forces. For the first time in two weeks, the Israelis allowed water to flow to the western sector.

Habib and Sharon, the chief architect of the Beirut siege, met for three hours at the residence of the U.S. ambassador in Yarze in the hills overlooking the capital. The meeting reportedly ended inconclusively.

Although Israeli officials remained publicly noncommittal about the details of their reply to the Shultz letter, Lebanese and Palestinian officials here were encouraged by what they saw as a new tone in Israeli pronouncements after the Cabinet meeting.

"The meeting went as well as could be expected," said former Lebanese prime minister Saeb Salam after talking with Habib following the U.S. envoy's session with Sharon. "I think he [Habib] is progressing. You can't expect the Israelis to change their position abruptly."

Sharon's comments echoed repeated Israeli statements that they have not been convinced that other Arab nations are prepared to accept the estimated 5,000 to 9,000 PLO fighters. But that view was challenged by sources close to the Habib negotiations who insisted that Iraq, Syria and Jordan have made firm commitments to give refuge to the guerrillas.

A fourth country, Egypt, has said that it too would be prepared to take in some of the Palestinians, but only as part of a wider agreement linking the PLO evacuation with an Israeli and American commitment to open serious talks on Palestinian self-determination.

Aside from Israeli skepticism over the commitments of the Arab nations, there also remained the question of a timetable for the deployment of an international military force in Beirut to take over the Palestinian positions when they are evacuated.

The PLO has backed off from its original demands that foreign troops be deployed between Palestinian forces and the Israelis prior to the start of the evacuation. It instead has agreed to begin pulling out of Beirut up to 24 hours prior to the arrival of the first international contingents--expected to be French paratroopers.

Israel is also said to be demanding a roster of those to be evacuated. Habib is reportedly waiting for such a list from the PLO.

As envisioned by the Habib proposal, the international force would be made up of 3,000 soldiers from the United States, France and Italy.

With the timing of the force's arrival still unsettled, Habib today met with military representatives from the three nations and from Lebanon to begin planning its eventual deployment and working out a logistical plan and timetable for the Palestinian evacuation.

A second meeting of this new military committee was scheduled for Monday, when sources close to the negotiations said they hope an overall plan can be completed that Habib can present to the Israelis.

The Habib plan already agreed to by the PLO and the Lebanese government reportedly envisages an initial departure by sea of 700 to 1,000 guerrillas. This first group of evacuees--made up of those Palestinians who do not wish to go to Syria--is expected to be loaded on foreign ships and taken via the Suez Canal to the Jordanian Red Sea port of Aqaba.

If Egypt agrees to take in some of the Palestinians, as Habib and the PLO hope, they will debark in Alexandria. If not, all will go to Jordan, where some will remain, while others continue on to Iraq.

The remainder of the guerrillas will be taken in a second phase to Syria. They are to go either by road to Damascus or by air if the Israelis who now occupy Beirut International Airport agree to allow its use.

Airport sources today indicated that the shell-battered airfield could be readied for emergency landings and takeoffs within 48 hours.

Salam, who has acted as a key intermediary between Habib and PLO Chairman Yasser Arafat, said tonight that if agreement could be reached with Israel, the PLO departure could begin in a matter of days and be completed in two weeks' time. There were unconfirmed reports that Habib hoped to bring a final proposal to Jerusalem in two days.

Before such a solution, Salam said, the "tug of war" now going on between Habib and Sharon would have to be resolved.

Many Lebanese and Palestinian officials here believe Sharon would prefer the total military destruction of the PLO and its leaders to letting the Palestinians depart for other Arab nations from where they might fight another day.

But the fact that the city's ninth cease-fire in nine weeks mostly has held for three days, coupled with the seeming momentum of Habib's mediating efforts, has given rise to some hopes that a peaceful resolution may be near.

Buoyed by the relative lull in the fighting since Friday, many West Beirut residents who had fled across the Green Line into Christian East Beirut last week after Israel's most intense bombardment of the city, today returned to the west. They drove across the shell-pocked no man's land to visit their homes and relatives, passing through the Galerie Semaan crossing point that is the only remaining link between the city's two halves.

But a round of shelling this afternoon between the Israelis and Palestinian forces brought a sudden halt to the traffic. The periodic thump of heavy artillery could be heard into the night from positions in the city's southern suburbs, a reminder that for all the new hopes for peace, the war is not over.

Correspondent Walsh added the following from Jerusalem:

Secretary of State Shultz's letter was received this morning by Begin, who after conferring with his Cabinet at its regular Sunday meeting sent a reply to Washington.

The Israeli Army radio report said that Begin told Shultz that Israel will vehemently oppose any unilateral move by another country to introduce troops into Lebanon. There were reports here that French soldiers, the vanguard of the international force, were on board a vessel off Cyprus. An Israeli official said the French had been warned not to send the troops to Lebanon without Israel's permission.

To back up that stand, Israeli military units took positions today in the Lebanese port of Juniyah, the likely landing site for outside troops.

A senior Israeli official described the Shultz letter as "important" and as a "preliminary" step before the United States relays to Israel a complete "package arrangement" for a PLO withdrawal. Begin's reply, he added, was to "make sure the Americans know our position before a package is sealed."

The official said the Israeli Cabinet remains willing to give the Habib mission more time and, like Begin, was encouraged by the contents of the letter from Shultz.

Attacks on Habib from Defense Ministry sources, widely published in the Israeli press today, gave rise to new questions about the Begin government's faith in the American diplomat. Asked about this today, Cabinet Secretary Dan Meridor said, "We all hope he will succeed."

Pressed on the issue, he added, "If we hadn't faith in him, we wouldn't wait, would we?"

In another development, Israeli ambassador to Britain Shlomo Argov, whose attempted assassination touched off the Lebanon invasion, was flown home tonight for further treatment of the severe head injuries he suffered in the attack.

[In Kuwait, tens of thousands of people shouted "Death to America, the enemy of the people" in a demonstration against Israel's invasion of Lebanon, Reuter reported. The procession was a rare event, because Kuwait has banned most public demonstrations since 1976.]