For the second time in 24 hours, Israeli warplanes attacked a suspected Palestinian guerrilla base in eastern Lebanon today, striking almost the same place the Israelis bombed yesterday.

A military statement said the target was a headquarters post of the Syrian-supported, rebel Palestine Liberation Organization faction headed by Abu Musa. The target was described as several huts and tents near the village of Taalabaya, behind Syrian lines along the Beirut-Damascus highway. [A Syrian Army spokesman in Damascus said the raid killed many civilians, but witnesses reported no deaths although they said 13 persons were injured -- four guerrillas at the building used as a base and nine girls hit by flying glass in a nearby convent school, Reuter reported. ]A spokesman for the Democratic Front for the Liberation of Palestine, the main pro-Soviet faction in the PLO, reported "heavy human losses among civilians" but gave no figures, The Associated Press reported.

Prime Minister Shimon Peres, speaking of yesterday's air attack against what was said to be a base of the Democratic Front for the Liberation of Palestine, described the renewed air operations as "preventive" and part of Israel's longstanding policy of striking at guerrilla bases when it has "concrete information" of plans to attack Israeli forces.

However, the air raids yesterday and today also appeared to be part of a stepped-up campaign of military pressure and reprisals following an increase in casualties suffered by the Israeli Army in southern Lebanon.

Yesterday the Israelis suffered one of their worst days in Lebanon in recent months when three soldiers were killed and three wounded in two incidents and a fourth died of wounds he suffered last week.

It did not appear that the increase in casualties will affect Israel's plans to begin a three-stage withdrawal from Lebanon next week with an initial pullback from Sidon and surrounding area. But two senior officials of the national unity government, Defense Minister Yitzhak Rabin of the Labor Party and Foreign Minister Yitzhak Shamir of the Likud bloc, gave differing interpretations of recent events in Lebanon.

Rabin, an architect of the withdrawal plan, warned that the longer Israel remains in southern Lebanon the more it risks transforming the territory's majority Shiite Moslem population into an active enemy. Shamir, one of six Likud ministers to vote against the withdrawal plan, said the most important factor was the safety of Israel's northern border, and he suggested that the withdrawal plan may need to be reevaluated.

Speaking last night at a Labor Party meeting in Haifa, Rabin said: "If the Lebanese war concludes with our having struck a certain blow, for a certain period, against the PLO in Lebanon, but in its place comes Shiite terrorism, this will be an extremely grave development from the point of view of the problems of terrorism that Israel will have to cope with."

Rabin said the withdrawal plan was "the least bad solution" to Israel's predicament in Lebanon.

Shamir, discussing the increased attacks on Israeli forces with reporters, said it was not clear whether this resulted from the withdrawal decision, but that the effects of the decision should be examined.

"The problem is to make sure that terrorism -- whether it is from Palestinians or Shiites -- will not endanger the security of the Galilee," he said. "It is on this basis that we should determine the pace of the withdrawal and whether it should be continued at all."