Today's Israeli raid on southern Lebanon, the deadliest ever along the tense border, is seen here as the likely beginning of a new spiral of violence in which the Palestine Liberation Organization hopes to force Arab powers to rally to its support.

Palestinian officials have refused to disclose casualties or to give any other indication how successful the Israeli raids against their camps were, but it is widely expected here that Israel's action will trigger new Palestinian attacks from southern Lebanon.

The Lebanese government, conscious that the southern part of the country still remains outside its military and political control, had a muted public reaction to the raid.

The PLO suggested unofficialy that extremist Palestinians had fired the rockets into Israel that triggered the reprisat raid. But Arab commentators here believe that PLO leadrs, including Yasser Arafat, see clear political advantages in increased hostilities in the border zone, the guerrillas' last toehold of military freedom in the Arab world.

Even moderate PLO leadrs have become increasingly suspicious in recent weeks that Arab governments may be getting ready to sell out the Palestinian cause by negotiating with Israel while excluding the PLO. Simultaneously, there have been signs of renewed Palestinian militancy in southern Lebanon.

By accepting a spoiling role in southern Lebanon, the PLO can forcefully remind Arab governments of the Palestinian potential for creating political trouble, particularly for Syria.

Strongly-worded support for the key state yet to come out publicly in favor of the current American peace initiative that has been rejected by the PLO.

Israel's heavy raid will make it more difficult for Arab governments to ignore the PLO, particularly at the Arab foreign ministers' meeting in Tunisia later this week. Syria and Lebanon had hoped to keep the sensitive question of southern Lebanon off the agenda in order to avoid the embarrassment of publicly airing the terms of the now-broken cease-fire in the region.

Before Lebanon agreed to the cease-fire, it had signed an agreement with the PLO that was an updating of the Cairo agreement which provides for a guerrilla presence in southern Lebanon - very different terms from the Palestinian evacuation sought by Israel.

PLO's refusal to pull out of southern Lebanon is also coming from the Soviet Union, whose ambassador here has delivered public warnings about Israeli intentions to attack southern Lebanon and also has given private messages of support, Arab sources say.

In this atmosphere, the outlook favors an escalaton of violence.

PLO analysts concede that fresh Palestinians attacks would play into the land of Israeli hawks, who want to see the PLO excluded from the peace process and kept under control as a threat to Arab governments and who also welcome the chance to alteate Lebanese moslems from the PLO by episodes like today's raid.

The same Palestinians seem convinced, however, that Israeli action will pressure Syria to be more militant in living up to its public pledges to the PLO.

The worst hit village in today's raid was Hazziyeh, which was obliterated by bombs that pulverized the stone houses and left at least 48 people dead in the rubble.

Hassiyet, which is situated in a natural bowl, apparently was identified by Israel as the source of yesterday's rocket barrage into Israel.

Palestinian guerrillas enjoy full freedom of maneuver throughout the border area south of the Litani River, the "red line" that Israel has made into an off-limits area for Syrian peace-keeping troops.

Hassiyeh had also attracted a large number of Lebanese Moslem refugees from villages even closer to the Israeli border that had been emptied by earlier Israeli shelling. Many victims in the raid today were these displaced Lebanese.

Israeli aircraft attacked several other lebanese villages in two separate sorties, and shells were reported falling in Tyre, the southernmost Lebanese port, which also escapes Syrian control.

Palestinian refuess camps around Tyre were hit, notably Rashideyeh and Boug Chemali, but PLO officials would not provide Palestinian casualty figures.