Israeli Force Strikes at Guerrillas in Lebanon : Mideast: Officials say Hezbollah’s rocket launchers are the target. Troops later withdraw to security zone, U.N. spokesman says.

Israeli tanks and troops on Thursday surged into two villages in southern Lebanon on what Israeli officials said was a mission to seek out Shiite Muslim guerrillas and destroy mobile Katyusha rocket launchers that have rained erratic fire on regions of northern Israel.

Although the maneuver escalated the fighting in the area and reminded observers of the events leading to the full-scale Israeli invasion of Lebanon in 1982, Israeli officials insisted that their military foray would be limited in time and scope.

Timur Goksel, a spokesman for U.N. forces in south Lebanon, said today that the Israeli troops had withdrawn to Israel’s self-proclaimed security zone in Lebanon.

“It is serious, but not very serious,” Prime Minister Yitzhak Shamir said Thursday of the incursion in which at least two Israeli soldiers and three guerrillas from the extremist Hezbollah movement were killed. “I think it will come to an end in a short time.”

A senior military official described the campaign as “very limited,” although some of the goals were wider than the publicly reported aim of removing the threat from the Katyusha rockets.

Israel is sending a message to the Lebanese government to rein in Hezbollah, the Iranian-backed Shiite nationalist group, the military official said. Although the Lebanese army has been active in disarming local militias, Hezbollah has been left on its own to operate against Israel and the Israeli-controlled anti-guerrilla buffer zone in south Lebanon. Israel also sought to display its muscle to Hezbollah, the official said, noting, “They must know they will pay a price for attacks on Israel.”

For most of three days preceding Thursday’s attack, Hezbollah guerrillas had fired short-range Katyusha rockets into the Israeli-occupied zone in south Lebanon, as well as into northern Israel. Israel responded with tank and artillery barrages from the buffer area onto and around Shiite Muslim villages.

The latest round of Lebanese fighting began after Israel, in a weekend helicopter attack, assassinated Sheik Abbas Moussawi, a leader of Hezbollah. His killing followed close upon a Palestinian raid on an Israeli army camp inside Israel in which three Israeli soldiers were knifed to death in their sleep.

But the timing was a cover: Israel, officials have said, had planned Moussawi’s assassination as far back as December in frustration over broken negotiations aimed at recovering an Israeli air force prisoner believed held in Lebanon.

Most of the 30 or so Lebanese rockets that have landed in Israel have fallen harmlessly in fields. One crashed into a bus station in Kiryat Shemona. It caused no injuries, although several bystanders were shaken and were taken to the hospital for observation. Another 70 or so projectiles fell in the buffer strip, making only noise.

In Lebanon, thousands fled the villages of Yater and Kafra in advance of the Israeli thrust. They had been warned of intense artillery fire by Gen. Antoine Lahad, the leader of the South Lebanon Army, Israel’s client militia along its northern frontier.

Reports from Lebanon said that the two Israeli soldiers were killed inside a house booby-trapped with explosives. Israeli military officials said the story was false but declined to detail the circumstances of the deaths.

U.N. peacekeeping troops tried to keep Israeli troops out of the villages. But Israeli bulldozers shoved aside U.N. vehicles blocking the road. “They didn’t do anything to stop the Katyushas,” complained an Israeli military official. “Why should they stop us?”

Two U.N. soldiers, part of a group from Fiji, were hit by guerrilla fire directed at the Israelis, Israeli officials said. Another two Fijians were wounded by Hezbollah gunmen who burst through a U.N. roadblock.

In New York, U.N. Secretary General Boutros Boutros-Ghali protested the Israeli incursion and demanded that the Israelis and their militia allies withdraw immediately. Boutros-Ghali said that Undersecretary General Marrack Goulding, the British diplomat in charge of U.N. peacekeeping operations, had delivered the secretary general’s protest and demand to Israeli Ambassador Yoram Aridor.

U.N. spokesman Francois Giuliani said that an Israeli column of 17 tanks and 22 armored personnel carriers had crossed the border at 7:30 a.m., Lebanon time. He said that the lightly armed U.N. peacekeepers, without firing weapons, tried to stop the Israelis but were “pushed aside.” He said the wounded Fijians were caught in the cross-fire between the Israel defense forces and Hezbollah but “we do not know who fired the shots.”

U.N. sources said that the peacekeeping forces in southern Lebanon now number 5,000, armed with pistols, rifles and machine guns. Their heaviest weapons are mortars, but these are used only to shoot up flares for illumination at night. Since 1978, when the Blue Helmets, as the peacekeepers are known, were first assigned to southern Lebanon, their casualties have totaled 184 killed and 276 wounded.

In comments on Thursday, Shamir had suggested that the aim of Israeli action would be to eliminate the Shiite militants. “We will continue striking at Hezbollah until it quits Lebanon,” he pledged. Suspicions were also raised that Israel might extend the buffer zone, which it controls with the aid of the South Lebanon Army. U.N. observers noted that a hill occupied on Thursday by Israeli troops was one that they had held for three years after the 1982 invasion. It was not a hill from which Katyushas had been fired, U.N. officials noted.

Defense Minister Moshe Arens evaded press inquiries on the point, saying, “We will not put up with attacks of Katyusha rockets on the civilian population.”

Hezbollah has replaced the Palestine Liberation Organization as the chief adversary for Israel in Lebanon. The group is connected to a web of extremist groups responsible for the kidnaping of Western hostages, the killing of others and numerous terrorist acts. Hezbollah is committed to expelling Israel and its allies from the south.

Lebanon expressed fear that Israel might hit the ill-equipped, skittish Lebanese army and reminded Syria of a pledge to defend the country from attack. Syria, through an official in Egypt, said only that it was “natural to defend our Lebanese brothers.”

The White House took a deliberately low-key approach to the latest incidents. President Bush refused to answer questions during a photo session.

But, “as we (have) said before, we’re concerned about the rising cycle of violence in the Middle East in recent days,” said Deputy White House press secretary Judy Smith. “We certainly regret the loss of life in Israel and Lebanon. We are urging all concerned to exercise maximum restraint and end the violence there.”

Times staff writers Robin Wright in Washington and Stanley Meisler at the United Nations contributed to this report.