Israeli jets bombed Palestinian guerrilla targets near Sidon today shortly after a town in northern Israel was hit by a rocket apparently fired from Lebanon. The Israeli raid, the second since Jan. 29, killed 10 persons and wounded 30, Palestinian and security sources said.

The raid came 1 1/2 hours after a Katyusha rocket crashed into a schoolyard in Qiryat Shemona, in northern Israel. Four Israeli F16 warplanes made six attack runs over guerrilla facilities at Mieh Mieh and Ain Helweh, two Palestinian refugee camps near Sidon, 24 miles south of Beirut.

Israeli officials said that four persons were treated at the scene of the Qiryat Shemona rocket attack for minor injuries and that school resumed shortly after, Washington Post correspondent William Claiborne reported from Jerusalem.

An Israeli Army command source said the air strikes were not a response to the attack on Qiryat Shemona, but were part of a continuing strategy of disrupting guerrilla activity in southern Lebanon.

Brig. Gen. Uri Orr, chief of the Israeli Army's northern command, said it was too early to tell whether the rocket attack -- one of several in the Galilee in recent weeks -- represented a new offensive by Palestinian and Shiite Moslem guerrillas in Lebanon.

The Israeli strike came one week after Salah Khalaf, the second in command in Palestine Liberation Organization Chairman Yasser Arafat's Fatah group, announced that Palestinian guerrillas expelled from Lebanon in 1982 were "back in positions from where they can resume attacks against the Zionist enemy."

It also coincided with reports that some Palestinian fighters were returning to camps near Beirut and in southern Lebanon. Palestinian sources in Beirut said Arafat's guerrilla faction was coordinating activity in the south with the radical Shiite Moslem Hezbollah.

Fatah and Hezbollah have begun working jointly to defy a ban by the less radical Shiite Amal movement against guerrilla activity launched from civilian centers in the south.

Palestinian commanders in Sidon confirmed today that some of their fighters were among the dead. Fatah leader Badi Abu Suleiman told reporters that three of his guerrillas were killed and 10 wounded. Abu Ghaleb, of the Palestinian Rescue Committee for the south, said his men removed nine dead and 24 wounded from the wrecked guerrilla bases. "Some were fighters, but I can't say how many," Abu Ghaleb said.

A large bomb dropped by one of the warplanes gouged a crater 20 yards wide and 15 yards deep in front of an apartment block. Black smoke still billowed from the edge of Sidon hours after the raid as rescue teams dug through the rubble to search for victims. The facade of one building was blown away, and another building housing a Fatah radio station was leveled.

Last Friday the PLO claimed that four of its guerrillas operating from Lebanon were killed in a clash with the Israelis in northern Israel.

Reliable sources in Beirut said, however, that the four guerrillas allegedly killed were actually not dead but were being held prisoner by Amal in the security belt. The sources said Amal is not eager to publicize this before its general congress set for April 4, to avoid criticism by the radical Hezbollah of its policy of discouraging military operations against Israel.

Meanwhile, at least five persons were killed and many more wounded today when shells and rockets hit the Christian Kesrouan coastal region and mountain resorts in the Metn area north of Beirut. The Christian-led Lebanese Army said an "antiarmor missile was fired at a Lebanese Army armored personnel carrier" near Bickfaya, hometown of President Amin Gemayel.

Without mentioning them by name, the Army accused Syrian forces of taking part in the escalation. "It has been established that such a weapon is not available to the militias, which means regular forces are openly involved in the Lebanese war," the Lebanese Army said.

Residents cowered in basements and bomb shelters for seven hours in the heaviest shelling since Syrian-backed leftist and Moslem militias sought to exert pressure on Gemayel to accept a stalled peace agreement last January. The Lebanese Broadcasting Corp., a television station run by the Christian militias, said rockets hit a power plant at Zouk Mikhael, setting parts of it on fire. Other radio stations said the power company at Karantina, on the east Beirut seafront, was ablaze, leaving Christian areas dark.

Yesterday, two bombs exploded in east Beirut in the latest of a series of attacks on Christian areas. One official of the Lebanese Forces, the chief Christian militias, blamed Syria for the mounting pressure against the Christians.

"The Syrians have found no other way out than to hit at the Christians with state terrorism and criminal bombardment," the Voice of Free Lebanon, a radio station run by the Lebanese Forces, said tonight.