The Israeli Cabinet gave advance approval for Israeli troops to allow Lebanese Christian militiamen to enter Palestinian refugee camps in Beirut last week, the prime minister's office acknowledged today.

Controversy continued here over Israel's role in the events that led to the slaughter of Palestinian refugees by the militiamen. Two Israeli newspapers reported that senior government officials were told as early as Friday morning that widespread killing was taking place in the camps, which were surrounded by Israeli soldiers, and failed to take any action.

According to eyewitness accounts from Beirut, the Christian militia forces were in control of the refugee neighborhoods until Saturday morning, and the killings went on through Friday night.

Yitzhak Navon, who holds the largely ceremonial post of president, today called for an independent inquiry into the massacre. Prime Minister Menachem Begin was considering setting up an investigating commission, Israel Television said, and the Cabinet was widely expected to approve establishment of the panel at a meeting Tuesday.

According to a report by Zeev Schiff, the respected military correspondent for the independent newspaper Haaretz, the massacre of the Palestinian refugees began Thursday night, and military and civilian government officials knew about it by Friday morning. A similar account was published today in the conservative newspaper Yediot Aharonot, which strongly supports Begin's government.

Begin's chief spokesman, Uri Porat, confirmed an Israeli Army radio report that the Israeli Cabinet at its meeting Thursday night was informed of a plan to allow the Christian Phalangist militia to enter the Shatila and Sabra refugee camps where the massacre took place.

Porat said that the Cabinet adopted a resolution approving the action, which he said was intended to root out the remaining Palestinian guerrillas in the area and never was intended to turn into the wanton killing of men, women and children.

Dan Meridor, the Cabinet secretary who attended the meeting, refused to confirm or deny that there was advance government approval for the entry of the Phalangist militia in the sprawling refugee camps on the southern outskirts of Beirut.

Porat also had no comment on a report in today's Jerusalem Post that Israeli intelligence officials had warned Begin and Defense Minister Ariel Sharon in advance of the likelihood of massacres if the Phalangist militia were allowed into the areas.

Government spokesmen denied that senior officials knew as early as Friday morning that the killings were taking place. However, the Foreign Ministry confirmed that on Friday morning Foreign Minister Yitzhak Shamir was told by Communications Minister Mordechai Zipori of reports of "shootings" involving civilians in the refugee areas.

Officials said Shamir asked Foreign Ministry personnel about the report and was told that they knew nothing about it. He therefore did not raise the subject when later on Friday he and Sharon met here with U.S. envoy Morris Draper.

In a personal account of the events of last week, Schiff wrote that he learned of the massacre Friday morning from Israeli Army officers and that he passed the information to an unidentified senior official who sources later said was Zipori. "What I knew should have been known to others," Schiff said in the article.

These and other media reports here today contradicted initial assertions by military and government officials that the Christian militia forces entered the refugee areas without Israeli knowledge or assistance and that the Israeli forces moved to stop the slaughter as soon as they learned what was happening.

By tonight, the Israeli military command still had not put out a full account of its actions late last week. But in response to questions, the Army spokesman's office and military sources confirmed that the Christian militia entered the refugee area with the approval of Israeli officers on Thursday night.

The spokesman and the military sources said that the Israelis first became suspicious of what was happening in the camps Friday morning but that it was not until Friday night that they had managed to order all of the militiamen out of the refugee areas. They refused to provide precise times for any of their actions and did not comment on the reports that the killings had continued Friday night.

As the reports surfaced that senior officials had been informed of the massacre long before there was any Israeli action to intervene, the political crisis for the Begin government and the international implications for Israel appeared to deepen.

One of Begin's government coalition partners, the National Religious Party, reportedly had joined President Navon in pressuring Begin to allow an investigation.

Palestinian leaders in the occupied West Bank and Gaza Strip today voiced their outrage at the Beirut massacre, and Israeli radio reported that Palestinian youths threw stones at vehicles and set tires on fire in disturbances in the West Bank cities of Ramallah and Nablus. Police dispersed the crowds with tear gas and rubber bullets, and there were no casualties, according to the report.

Throughout the day, Israeli officials vehemently denied any Israeli complicity in the massacre and sought to shift the responsibility for failing to prevent it to the Lebanese Army.

At a special briefing called for foreign correspondents, a high-ranking government official said that beginning shortly after the Israeli Army's entry into West Beirut Wednesday morning, Israel had suggested through intermediaries that the Lebanese Army occupy the Palestinian refugee centers.

"If the Lebanese Army had moved into the camps when we asked them to, there would not have been any killing," he said.

The official, who spoke to reporters before it was known that the government had authorized the Phalangist militia to enter the refugee areas, said that the militiamen passed by Lebanese Army positions and that the Lebanese could have "sounded the alarm" when they saw them. He said the Israelis considered the Phalangist militia to be a disciplined military force and never dreamed that it might engage in indiscriminate killing of Palestinians.