JERUSALEM, APRIL 20 -- Khalil Wazir, number two leader of the Palestine Liberation Organization, was gunned down by an Israeli commando squad after the assassination was approved by Israel's policy-making inner cabinet, according to informed sources here.

Israel has lowered a curtain of official secrecy over the operation. But with information compiled from a Tunisian investigation and from Israeli sources, it is possible to assemble some of the key pieces in the secret story of how the raid was planned.

The operation was planned and carried out by a combined team from the Mossad spy agency, the Army, Navy and Air Force, but the actual assassination early Saturday morning in Tunis was carried out by a special Army commando unit known in Hebrew as the Sayeret Matkal, sources said. The name translates as "reconnaissance party of the general staff."

The raid was overseen by several senior military commanders in a specially equipped Boeing 707 who were in constant radio contact with the squad on the ground.

The 10-member inner cabinet discussed the assassination twice before approving it, once immediately after last month's terrorist bus hijacking in the Negev desert in which three Israeli civilians were killed and again last Wednesday. No formal vote was taken at the second session, but the only dissenting voice was that of Ezer Weizman, a former defense minister.

Foreign Minister Shimon Peres, who raised objections at the previous session, was silent at the Wednesday meeting, the sources said. Education Minister Yitzhak Navon, who also had objected to the plan, was overseas and did not attend.

Despite the fact that Israel has not publicly acknowledged ordering and carrying out the killing, the assassination has caused widespread elation here and boosted morale both among the public and in the Army, which had been worn down and disheartened by several recent incidents and the grinding rigors of fighting the four-month-long Palestinian uprising in the occupied territories.

Israelis have pointed to the careful planning, efficiency and "humaneness" of the attack -- the fact that only Wazir and three of his bodyguards were killed, while his wife and child were spared -- as proof that when it comes to such operations, Israel is still the world leader.

But the early jubilation, shared by both the liberal left and far right, over the killing of a man branded as a senior Palestinian terrorist, has begun to fade. Some Israelis have warned that the assassination is an artificial quick fix that, on the eve of Israel's troubled 40th anniversary, illustrates the country's inability to find a political solution to the problem of coping with the Palestinians both within and outside its borders.

Such an operation, wrote Yoel Marcus, columnist for the Hebrew daily Haaretz, "is good for our egos, but doesn't deal with the serious problems facing our country." Israel, he warned, is reverting to "the same methods and tools that were appropriate 20, 30, 40 years ago. The Abu Jihad assassination is a symbol of what is happening to us."

At best, these critics contend, the assassination will be a serious short-term blow to the already fragile Middle East peace process. At worst, it could reignite the secret war in which dozens of Palestinian operatives, Israeli diplomats and innocent civilians were gunned down in the 1970s.

For several days, Israel's official silence, enforced by military censorship, was effective in concealing the government's role, even though the modus operandi clearly was Israeli. While the PLO, the Arab states and the Israeli public all knew who had committed the act, the official silence allowed Israel to dodge international condemnation.

But the silence has frayed. Weizman has spoken out against the operation, tacitly acknowledging Israel's role by noting that until last week, Israel for several years had adhered to an unwritten agreement not to attack PLO leaders. "The fact is that we have never done so -- why now?" Weizman asked.

Asked by reporters whether Israel ordered the killing, Weizman replied, "Guess for yourselves."

Even Prime Minister Yitzhak Shamir, while condemning Weizman's comments, has not been able to restrain himself from broad hints. At a memorial ceremony for Israeli war dead last night, Shamir said, "Let's hope that our enemies will realize and understand that Israel knows how to wage war, and that all those who hurt us will be hurt manifold."

Shamir's only reported direct comment on the assassination came on Sunday when, Israeli radio said, he told Cabinet members at their weekly meeting, "I heard about it on the radio, just like you."

Security officials reportedly have discussed assassinating Wazir for many years, but the operation gained new impetus after the March 7 Negev bus attack, for which Wazir's Fatah military organization claimed responsibility.

The inner cabinet, made up of five senior ministers each from the rival Labor and Likud political blocs in the coalition government, first discussed the issue on the day after the bus hijacking. Security forces were given a yellow light to prepare an attack, sources said, but the final decision was postponed.

Last Wednesday's inner-cabinet discussion took only 30 minutes, sources said. Yossi Ben-Aharon and Yossi Beilin, the senior aides to Shamir and Peres respectively, were asked to leave the room. Weizman raised his objection while Peres reportedly remained silent. "Based on the previous discussion, it was understood he was not crazy about the idea," a source said of Peres.

Those who had originally opposed the plan -- Weizman, Peres and Navon -- are all members of the Labor Party, the more dovish half of Israel's shaky coalition. The other two Labor ministers in the inner cabinet, Defense Minister Yitzhak Rabin and Police Minister Haim Bar-Lev, both supported the assassination, according to sources. Shamir, in keeping with past practice on sensitive security matters, did not ask for a show of hands.

The mission had several objectives, sources contend. One was to punish the PLO for the bus attack and send a warning that no Palestinian leader -- even the heavily guarded, security-conscious Wazir -- was safe from retaliation. The other was to deflate the uprising, which had begun spontaneously last December but in which Israeli officials believed Wazir played a major coordinating role in recent months.

The Army was also in need of a boost to its morale and self-image after last November's hang-glider attack in which a lone Palestinian commando killed six Israeli soldiers and injured a dozen others before he was killed.

The Army's image suffered further damage in the March bus attack because the hijackers, after infiltrating into Israel, drove to the site in an Army sedan they seized from three Army officers they ambushed. The officers, on their way to a track meet, were out of uniform and unarmed and fled. They were later severely disciplined.

Three of the Army's top commanders have experience with raids such as the one against Wazir. The chief of staff, Gen. Dan Shomron, led the raid on the Entebbe, Uganda, airport in 1976 that freed a hijacked jetliner. His deputy, Maj. Gen. Ehud Barak, led a 30-member commando squad that killed three major PLO leaders and dozens of Palestinian guerrillas in Beirut in 1973. The commander of that operation, Gen. Amnon Shahak, is now head of military intelligence.

Analysts say the assassination especially fits the strategic thinking of Barak, a commander who favors swift, limited strikes over grand-scale operations.

As in the Beirut raid, a three-man Arabic-speaking Mossad advance team entered Tunis using false Lebanese passports, reconnoitered the area and arranged for rental vehicles for use by the hit team. Some 30 to 40 commandos were ferried to an isolated seashore site in rubber dinghies launched from a missile boat manned by the Navy's seaborne commando force.

Some reports said the attackers were wearing uniforms of the Tunisian National Guard, although this could not be confirmed here.

While the raiders were approaching their target, a Boeing 707 equipped like an American airborne warning and control system aircraft, with sophisticated electronic gear, was flying over the Mediterranean just outside Tunisian air space. The plane was used not only to jam telephone communications around Wazir's home, as Tunisian investigators have charged, but also to monitor and coordinate the entire operation.

Senior military commanders were aboard the plane and a source whose account cannot be confirmed said among those present were Barak, Air Force Commander Avihu Bin-Nun and, possibly, Shahak. The operational commander on the ground has not been identified.

Tunisian officials said the Boeing used a civilian radio signal designated as 4X. According to an account in Haaretz today, that signal is used by Israeli military aircraft and indicates the plane was on Flight Path Blue 21, a route between Sicily and northern Tunisia that is under supervision of Italy's aviation authority, not Tunisia's. Thus the plane could have remained in the area without Tunisian knowledge.

A similar Boeing, painted over to look like a civilian El Al airliner, served as operations center during the Entebbe raid. Those aboard included one of Barak's predecessors, Maj. Gen. Yekutiel Adam, and the then-commander of the Air Force, Maj. Gen. Benny Peled.

The actual attack on Wazir's house took only minutes. The three guards were killed by silenced weapons and Wazir was mowed down when he emerged from his study with a pistol.

In the 1973 Beirut operation, a number of innocent bystanders were killed, including the wife of one of the targeted PLO officials, along with two Israeli commandos. This time, sources say, the only Israeli casualty was one wounded commando.

A senior military officer, who refused to confirm or deny the above account, nonetheless said the operation would boost Army morale. "Here's one of the top terrorist leaders and planners and he gets hit in his home thousands of miles from Israel," said the official. "That has to restore some of the deterrent factor that may have been lost after the hang-glider attack."

It has also restored the confidence of many Israelis. Israeli television last Saturday night carried part of an interview from Tunis with Wazir's teen-aged daughter, in which she described to foreign reporters the terrifying scene when she and her mother stepped out of their bedrooms to find her father lying in a pool of blood and armed strangers standing around his body.

Her mother turned her back and put her head against the wall, awaiting an executioner's bullet, the daughter recalled. But instead, she said, one of the men, speaking Arabic with a heavy Hebrew accent, told the girl, "Go tend to your mother." And with that the men left -- and the assassination of Abu Jihad entered into Israeli legend.