Jerusalem — There are increasing signs that Israel's newly formed government is serious about finding a way to end this nation's two-year occupation of southern Lebanon.
In speeches made during his first week as prime minister, Shimon Peres said he hoped that Israel will be able to withdraw its troops ''in a matter of several months.''
And the Peres-led national-unity government has indicated that it is willing to be more flexible about its terms of withdrawal than was the Likud government.
In the past, Israel insisted on two things occurring before it would withdraw from the south. The first was that Syria simultaneously withdraw its forces deployed in eastern Lebanon's Bekaa Valley. The second was that the security of Israel's northern border be assured.
But the new government has conceded that the Syrians will remain in the Bekaa after Israeli troops are withdrawn from the south. Foreign Minister Yitshak Shamir said over the weekend that Israel no longer demanded Syria's withdrawal and hoped that the United States would act as a mediator between Syria and Israel.
And in the last week, at least some government officials seem to have changed their views on what is the best way to guarantee Israel's security in southern Lebanon. There are some signs also that Syria is now interested in facilitating the Israeli withdrawal from Lebanon.
Said one Arab diplomatic source in Amman, ''There are three Syrian advantages in an Israeli withdrawal now. The Syrians can say to the Americans, 'Look, we can make peace and we can make war in Lebanon.' They can say to the Arabs, 'We got the Israelis out, and we gave them nothing,' and they can bolster their prestige domestically.''
One player taking advantage of the changing mood in both Israel and Syria toward southern Lebanon is UNIFIL, the United Nations force that has been deployed in south Lebanon since 1978.
UN Undersecretary-General Brian Urquhart was shuttling among the Israelis, Syrians, and Lebanese last week, ostensibly discussing renewal of the mandate for UNIFIL forces in southern Lebanon. But Mr. Urquhart expressed optimism that all three parties now see the expansion of UNIFIL's role as a peacekeeping force in south Lebanon as one solution to Israel's security demands.
That marks a sharp reversal for the Israelis. The Likud government that just left office was openly contemptuous of UNIFIL, but the new government, and in particular Defense Minister Yitzhak Rabin, has publicly praised UNIFIL's past actions in the area.
UNIFIL has made it clear that it will only agree to expanding its role in conjunction with an Israeli withdrawal from the south.
Undoubtedly, one reason for the Israelis' new-found respect for UNIFIL is last week's disaster with the Israeli-backed South Lebanon Army (SLA).
For months, the Israelis have been building up the SLA and its Christian-Lebanense general, Antoine Lahad. The Israeli position has been that as General Lahad's forces grew - there are now 2,100 mostly Christian SLA troops in predominantly Muslim south Lebanon - they could take over security patrols in a widening area, allowing Israeli troops to gradually pull back.
''You will not see us leave overnight. We will turn areas over to them gradually, but we will be behind them, to enforce them,'' said a senior Israeli military source.
But last week, the Israelis' hopes for the SLA received a jolt after SLA regulars massacred 13 Shiite villagers in southern Lebanon. Some 30 people were injured.
The massacre occurred hours after three Druze members of the SLA were killed in an attack in a south Lebanese village Thursday. After the attack, the SLA and Israeli intelligence officers rounded up for questioning more than 200 men from Sukmour, a Shiite village. While the men were being questioned, a group of about 15 Druze members of the SLA drove into the village and opened fire on the villagers, according to news reports.
The day after the attack, a senior defense source was quoted in an Israeli newspaper as saying that the massacre showed how little the Israelis can depend on the SLA.
Israel's concerns about security for its northern towns and settlements, however, remain. The occupation is increasingly unpopular in Israel, where newspapers daily print accounts of sniper attacks on Israeli troops and list the number of troops killed - now close to 600.
But no Israeli government could survive if it pulled out of Lebanon and katushya rockets began falling on Israeli towns and settlements in the north the next day. So the Israelis are bound to move very cautiously toward any withdrawal agreement.
One scenario discussed here would include an informal agreement arranged between intermediaries between Syria and Israel whereby Syria would agree to control hostile Shiite or Palestinian guerrillas in their area. The Israelis would pull back and allow UNIFIL to expand its deployment to the north, east, and south. The SLA might remain as a buffer in a narrow strip directly above the Israeli border, operating informally alongside UNIFIL.
One missing link until last weekend was American involvement. Some officials close to the negotiations had said it was important that the Americans renew their interest in south Lebanon and concentrate on openly recognizing the Syrian dominance of the situation.
Tragically, the bombing last week of the US Embassy in Beirut seems to have provided an opening for the United States to resume its role as mediator between Israel and Syria.
Following the bombing, the Americans sent Richard Murphy, assistant secretary of state, to Beirut to investigate its causes. Mr. Murphy, former ambassador to Syria, also made an unannounced visit to Damascus.
The atmosphere for an Israeli withdrawal is hopeful for the first time in recent memory. But all those involved are aware that in the explosive world that is Lebanon, innumerable obstacles will arise in the peaceful resolution of at least one of this nation's problems.