Israel buried 12 soldiers today, the victims of yesterday's suicide truck-bomb attack just north of the Israeli-Lebanese border, and amid the expressions of shock and grief there was a rising chorus of demands for an immediate withdrawal from what one politician termed "the Lebanese hell."

While the Israeli Army struck back swiftly today, killing 34 persons described as suspected Shiite Moslem guerrillas in an attack in southern Lebanon that a spokesman denied was retaliatory, senior government officials here declared that Israel's withdrawal timetable would not be affected by the growing violence.

"The terrorists will not determine our plans, we will determine them ourselves," Prime Minister Shimon Peres said in a visit tonight to some of the 14 Israeli soldiers wounded in yesterday's incident and being treated in a hospital in Tel Aviv. Acknowledging the mounting criticism of the protracted withdrawal plan, Peres added, "We'll get out, not in panic, not in surrender, and anyone who endangers the life of an Israeli soldier will be fired on in return."

Nevertheless, the suicide truck-bomb attack, which occurred just a few hundred yards north of the Israeli border and raised to 16 the number of Israeli soldiers killed in Lebanon since the withdrawal began last month, renewed the questioning of the timetable of the three-stage withdrawal, which is not due to be completed until late this summer.

Several left-wing members of parliament said they will introduce resolutions before the Foreign Affairs and Defense Committee Tuesday calling for an immediate Israeli withdrawal from Lebanon.

"It is clear that so long as the Israeli Army occupies Lebanese land it will be a target for such ghastly attacks," Victor Shemtov of the Mapam faction in parliament said. "Our Army has become part of the Lebanese hell in which a war is being waged beyond all norms of morality. . . . There is no justification, military or political, for remaining in Lebanon."

Most of the calls for an immediate pullout came from left-wing opposition members of parliament, but they were supported by some members of the ruling government coalition, including Abba Eban, the chairman of the Foreign Affairs and Defense Committee, and Amnon Rubinstein, the communications minister. But more than balancing this criticism was the attitude of members of the right-wing Likud Bloc, the main partner with Israel's Labor Party in the national unity government.

Most Likud ministers opposed adoption of the withdrawal plan and have only reluctantly gone along with its implementation. While there are military and logistical arguments against an immediate Israeli withdrawal from southern Lebanon, the elaborate three-stage plan adopted by the Israeli Cabinet in January is widely believed here to represent a political compromise between the Labor Party and Likud, which launched the June 1982 invasion of Lebanon.

Summing up the Likud attitude, Deputy Foreign Minister Ronnie Milo said today that Israel "should stand firmly in Lebanon to avoid any interpretation by the terrorists that by such actions they can push Israel back from other places."

Milo referred specifically to the Israeli-occupied West Bank and Gaza Strip as places where armed resistance might be encouraged by a hasty Israeli retreat from Lebanon.

Other government officials, including Labor Party ministers, argued that for Israel to speed up the withdrawal timetable now would give the impression of "panic" and encourage the Shiite guerrillas to continue their assaults across the border into Israel itself.

In an interview, Police Minister Haim Bar-Lev, a former Army chief of staff, said, "I don't think we should do anything hastily because of this last incident, but we also shouldn't waste any time. The timetable the government has adopted is apparently the right timetable." Similar sentiments were expressed by Defense Minister Yitzhak Rabin. In a radio interview today, he rejected an immediate withdrawal from Lebanon "because we must consider what will happen after we do that."

He added, "There is no certainty that the extremist Shiite elements in Lebanon do not desire to go on striking at Israel. Therefore, we must take into account, in the implementation of the [Israeli military] redeployment, a perception of the future as well: How will we live along the northern border with reasonable security for our settlements?"

Last month, the Israeli Army executed the first stage in the withdrawal, pulling back from Sidon and the surrounding area. The Cabinet last week authorized the Army to complete the second stage -- leaving the positions the Israelis now hold in eastern Lebanon -- as soon as possible.

According to military officials here, it will not be possible to pull out of the snow-covered mountains of eastern Lebanon until warmer weather arrives, probably in April. The Israelis then plan to hold the new line for several months, finally pulling back to a "security belt" north of the Israeli border in late summer.

Critics of this plan argue that while weather may dictate how soon the Israeli Army can evacuate the mountains of eastern Lebanon, there is no reason to continue to hold the present Israeli defense line at the Litani River along the Lebanese coast. This area, east of Tyre, is the center of Shiite resistance to the Israeli occupation and the site of the clashes with the Lebanese Army.

The critics, who still appear to be a minority in the government, argue that the planned second and third stages of the withdrawal should be combined into a single move back to the security belt as soon as it is possible to evacuate the eastern Lebanese mountains.

Rabin said today there were no plans now to clear the proposed security belt of its civilian population in order to prevent attacks on Israeli forces that will continue to patrol the area after the withdrawal. However, in the aftermath of yesterday's truck-bomb assault, Israel did take additional protective measures.

The Army extended to all of southern Lebanon south of the Litani River a requirement that all vehicles on the roads contain at least one passenger in addition to the driver. The requirement, first imposed last month around Tyre, is meant to discourage suicide car bomb attacks.

The Israelis also required trucks using a bridge across the Litani River near the scene of yesterday's attack to be unloaded by hand before proceeding.