Twelve Israeli soldiers were killed and 14 wounded today when a pickup truck carrying explosives and driven by a suicide bomber blew up near a troop transport a few hundred yards north of the Israeli-Lebanese border.

The incident, near the Israeli border town of Metullah, was the most serious attack on Israelis in Lebanon since November 1983, when a suicide car bomb blew up an Army headquarters in Tyre, killing 28 Israelis and 32 other persons, mostly Lebanese and Palestinians being held for interrogation.

Two militant Shiite Moslem groups said in calls in Beirut that they had carried out today's bombing, with one of the callers saying the original target had been the town of Metullah.

The Israeli vehicle was near the middle of a military convoy that had just crossed the border into Lebanon when it was destroyed by the Lebanese truck. The wounded Israeli soldiers, several of them said to be severely burned and in critical condition, were taken to hospitals in Haifa, Safed and Tel Aviv.

Israeli military officials said the truck was believed to be carrying at least 200 pounds of explosives.

Israeli Army radio said soldiers in a jeep leading the convoy waved the approaching truck off the road. It said the driver then set off the bomb, killing himself and destroying the passing Army vehicle.

The extent of the carnage, the methods of the attacker and the closeness of the incident to Israel's border were seen by observers as further indication that Israel's nearly three-year-old occupation of southern Lebanon has helped transform the majority Shiite Moslem population into bitter enemies of Israel and lent credibility to the threats of Shiite leaders to carry their attacks across the Israeli border.

The incident is expected to spark renewed questions here over the long-term consequences of Israel's recent crackdown against Shiite villages in Lebanon that have been centers of resistance to its occupation.

In Beirut, a caller saying he represented the Lebanese National Resistance Front told Agence France-Presse that the bombing had been carried out by his group in retaliation for a car bomb explosion Friday outside a Shiite mosque in a suburb of Beirut that killed as many as 80 people and wounded more than 200, special correspondent Nora Boustany reported.

The Islamic Jihad organization also claimed responsibility, Reuter reported. A caller said: "The car bomb was originally prepared to blow up the Israeli village of Metullah. A tactical mistake by one of our colleagues forced us to blow it up near an Israeli military post."

Sheik Mohammed Hussein Fadlallah, Lebanon's senior Shiite religious figure, charged in an interview with a Druze-run news agency in Beirut today that the United States was behind the mosque explosion Friday.

He described it as a "preemptive crime" by the United States before it casts an expected veto at the U.N. Security Council on a Lebanese resolution condemning Israel's actions in southern Lebanon. "The people who are suffering from the policy of America, which is allied with Israel in the region, know how to respond," Fadlallah said.

The United States has denied any involvement in the explosions. Israel also has denied responsibility for the Beirut explosion or for a bomb in a Shiite religious center in Maarakeh in southern Lebanon a week ago that killed 12 people.

Today's attack occurred at almost the same spot where two Israeli soldiers were killed earlier this year by a roadside bomb.

Today's casualties raised the Israeli toll in Lebanon to 18 killed and 28 wounded since the Army began its planned three-stage withdrawal on Feb. 16. Israel has suffered 634 killed in Lebanon since its June 1982 invasion.

Until today, Israel's crackdown against Shiite villages in southern Lebanon appeared to have reduced Israeli casualties, although it had not cut the number of attacks on its forces. Five Israeli soldiers were wounded in what was described here as 13 incidents on Friday and Saturday.

The area where the convoy was attacked today has been under the control of Israeli-backed Lebanese militiamen since 1978 and is part of what Israel describes as a "security belt" that its forces will continue to patrol even after withdrawal.

The attack on the Israeli troop transport came shortly after Prime Minister Shimon Peres had issued a statement condemning the use of car bombs in Lebanon, an unusual move meant to buttress Israel's denial of responsibility for Friday's blast in the Beirut suburb. Peres also defended the Army's tactics of massive searches, arrests and destruction of homes in Lebanese Shiite villages as necessary to protect the lives of Israeli soldiers.

Yossi Beilin, the Cabinet secretary, quoted Peres as declaring at today's Cabinet meeting that Israel "opposes the use of car bombs and the murder of innocent people" and that it "condemns the recent attacks of this nature in Lebanon and deeply regrets the innocent victims of these terrible deeds."

According to Beilin, Peres added that while Lebanon's Shiite population was not viewed as enemies of Israel, "every army has the right to defend its soldiers and there can be no compromise in regard to the attempts to attack Israeli troops" in southern Lebanon.