Jerusalem — The Israeli government appears likely to keep its troops in Lebanon over the next few weeks in accordance with the wishes of the United States. Prime Minister Menachem Begin is likely to hold to this position, say well-informed sources close to the government, despite mounting domestic concern over escalating Israeli casualties in Lebanon inflicted by Palestinian and Lebanese irregulars often operating from behind Syrian lines.
Israel's opposition Labor Party has called for a partial Israeli pullback in the next few weeks and total withdrawal from Lebanon over the next three months.
US officials, grappling for a strategy to convince Syria to accept the recent Israel-Lebanon accord on Israeli troop withdrawal and to pull Syrian forces out of Lebanon, have become increasingly nervous that Israel might soon pull back unilaterally.
A partial Israeli pullback to more defensible lines along the Awali River - 45 kilometers north of the Israeli border - would set the stage for a de facto partition of Lebanon between Israel and Syria. It would also undermine the government of Lebanese President Amin Gemayel, to whose survival the US is heavily committed, by creating a vacuum into which Syrian and Palestinian forces could move.
The Israeli news media have been reporting that American officials are convinced that the Syrians will leave only under continued Israeli military pressure. Some of the Israeli troops in Lebanon are only 25 kilometers from Damascus. Israel's deputy foreign minister, Yehuda Ben-Meir, told reporters recently that senior US officials had urged Israel not even to speculate publicly about any withdrawals, since this would ease pressure on the Syrians.
Thus a topsy-turvy situation has emerged. The US, which anxiously urged Israel to agree to quit Lebanon, now wants the Israelis to stay. The governing Likud coalition, estranged from the Reagan administration because of the Lebanon war, is now back in excellent American graces thanks to the astute policies of new Defense Minister Moshe Arens, the signing of the accord with Lebanon, and a willingness to cooperate with the Americans even though almost nobody in the government believes the Syrians will withdraw from Lebanon.
And the Labor Party, which top US officials only recently courted openly, has incurred US displeasure by pressing for a speedy unilateral Israeli withdrawal.
''For the first time in a long time there is a broad understanding between Israel and the United States which I think will last for a long time,'' says Likud member of Knesset (parliament) Ehud Olmert, a rising young party figure.
Defense Minister Arens spoke last week of the need for ''urgent consultation'' with the US and Lebanon if Syria does not pull back ''in the next few weeks.'' Mr. Olmert thinks Israel might wait ''up to six months.'' If the Syrians and troops of the Palestine Liberation Organization refuse to budge, the Likud would then pull back, presumably to the Awali, and remain indefinitely.
But Moshe Shahal, leader of the Labor alignment in the Knesset, insists, ''It is not a question of a few months. It is a question of the lives of our soldiers. If the US has an interest in Lebanon, it can't just ask Israel to do the dirty job of staying there.'' Labor would recommend that multinational forces, now stationed in the Beirut area, would take over vacated areas in central Lebanon, and the forces of Israel's Lebanese ally, Maj. Saad Haddad, would patrol south Lebanon.
Whether the Israeli public supports the government or the opposition stand will depend in large part on the future casualty toll. Military analysts here point out that one serious incident taking 40 to 50 lives could generate pressure for an immediate pullout.
Mr. Olmert says the public mood will depend on ''the degree of self-confidence shown by Mr. Begin and the Cabinet.''