Israeli warplanes bombed and strafed Palestinian guerrilla positions along the coast of Lebanon today, and Palestinian gunners retaliated by shelling the Galilee region of northern Israel in the most serious breach yet of the fragile, 10-month cease-fire between the two sides.

Lebanese officials said at least 16 persons were killed and 56 wounded in the raids, which the Israeli Army Command said Israel's Cabinet ordered against three Mediterranean coastal bases "after terrorist organizations during the past days repeatedly and severely violated the cease-fire arrangement."

The Associated Press reported from Beirut that inland guerrilla strongholds were hit by Israeli naval vessels. The guerrillas said they returned the fire with missiles.

Less than an hour after the air strikes, Soviet-made Katyusha rockets presumed to have been fired from Palestinian positions in Nabatiyeh, southern Lebanon, fell in the Galilee panhandle near the Israeli border. No casualties or damage were reported.

Because of censorship restrictions, the targets in Israel were not officially disclosed, but reports from the northern Israeli town of Kiryat Shmona said residents there had been ordered by police to spend the night in bomb shelters. Israeli television reported tonight that at least 150 shells were reported by residents of the northern border area.

It was the first direct exchange of cross-border fire between Israel and the Palestine Liberation Organization since the two sides, through the mediation of U.S. special envoy Philip C. Habib and the U.N. peace-keeping force, agreed to a cease-fire July 24 following the "mini" war of attrition last summer.

The State Department expressed "concern about what is happening" and issued a call to all sides "to exercise restraint and caution." In addition to contacts through the U.S. embassies in Beirut and Tel Aviv, U.S. diplomats were reported to be making contact with the Palestinians through third parties in the region.

An Israeli Army Command spokesman said Israeli jets bombed an arms depot and bunkers at Mazrat Vista, three miles south of Zahrani, where the Zahrani River flows into the Mediterranean; a training base of Fatah, the main military arm of the PLO, in Dahar Aklun, three miles south of Damour, and two 100 mm artillery guns positioned near Sidon.

The Army Command said that Palestinian antiaircraft guns along the coast opened fire on the attacking Israeli planes and were bombed also.

An Army spokesman cited four recent alleged cease-fire violations that prompted today's air strikes:

The wounding of an Israeli soldier by a land mine on April 30 near the southern Lebanese village of Debel. Several hours before the mine exploded, guerrillas opened fire with light arms and mortar on local civilians in an area controlled by a Dutch unit of the U.N. peace-keeping force, officials said.

The placing of land mines Friday on a border patrol road near Har Dov, an Israeli border kibbutz. Israeli Army helicopters penetrated southern Lebanon after the discovery of the mines, and soldiers abducted four Lebanese shepherds, who were released 10 hours later when it was determined that they had nothing to do with the mines, Army officials said.

The wounding of an Israeli boy and girl today when an explosive device went off on a civilian bus in Jerusalem.

The placing of a bomb near a school in the Israeli city of Ashkelon last week.

Today's air strikes were the most extensive since April 21, when a land mine killed one Israeli soldier and wounded another in the border enclave controlled by Christian militias under Israeli ally Maj. Saad Haddad. Israeli Air Force jets bombed three Palestinian guerrilla bases in Lebanon and shot down two Syrian Mig 23 jets.

The Voice of Lebanon radio in Beirut today said that Syrian interceptors were in the air during today's air strikes but did not attempt to engage the Israeli planes.

Meanwhile, Israel's Cabinet reiterated in strong language today that if Egypt continues to refuse to conduct West Bank-Gaza Strip autonomy negotiations in Jerusalem, the talks will not be held at all.

In a communique read by Cabinet Secretary Dan Merridor, the government declared, "It is understood that these negotiations will take place in the capitals of the three participating nations, namely Jerusalem, Cairo and Washington . . . . It is inconceivable that Israel would agree to boycott Jerusalem as one of the three capitals in which the negotiations will be continued."

A similar statement was approved by Israel's parliament on May 4.

Egyptian President Hosni Mubarak has said that Egypt will negotiate autonomy in any Israeli city but Jerusalem, because of Jerusalem's disputed status.

U.S. special negotiator Richard Fairbanks is scheduled to begin a round of talks here and in Cairo in an effort to break the impasse over the venue of the autonomy negotiations. The United States has proposed Washington as a compromise venue, but Israel has rejected that suggestion.