With a new cease-fire between Israeli and Palestinian forces holding today, U.S. special Middle East envoy Philip C. Habib resumed intensive mediation efforts to break a deadlock in negotiations to send Palestinian guerrillas out of Lebanon and lift the Israeli siege of West Beirut.

During Habib's latest visit to Jerusalem, Israel reportedly asked him specifically to extract an answer from the Palestine Liberation Organization on whether it was prepared to leave Lebanon. In effect, the response came today at an Arab League ministerial committee meeting in Jeddah, Saudi Arabia, when the chief PLO delegate, Farouk Kaddoumi, signed a statement repeating the essence of a written commitment to withdraw made July 3 by Chairman Yasser Arafat.

Both statements, however, left open the questions of how, when and where the estimated 5,000 to 6,000 Palestinian guerrillas trapped in Beirut would go. The PLO appeared to feel itself under no immediate pressure for a quick decision on these issues. Lebanese negotiators insisted there was no 48-hour Israeli deadline as reports from Jerusalem yesterday suggested.

According to informed PLO officials, the guerrilla organization basically has not budged from its conditions, which include the introduction of international peace-keeping units, a disengagement of Israeli and Palestinian forces, and negotiations between the PLO and the Lebanese government on the future Palestinian presence here. The PLO insists that any withdrawal from Lebanon must be simultaneous with Israel's pullout, whereas Israel and Habib have been demanding that the Palestinians leave first.

As distributed by the Saudi news agency, today's statement in Jeddah maintained similar conditions.

According to Palestinian and Lebanese officials, the latest U.S. peace efforts have produced little visible progress toward a rapid settlement of the crisis. However, there were other indications late tonight that behind-the-scenes wrangling in Lebanon and Saudi Arabia has raised some hopes of movement toward an agreement.

The hopes were founded on reports that Habib has told Lebanese President Elias Sarkis he has secured agreements to satisfy PLO conditions for withdrawing from Lebanon. In addition, the radio of the Lebanese Christian Phalangist militia reported an accord was in the making that provided for an Israeli pullback from Beirut, the departure of PLO guerrillas now in West Beirut for Syria and a staged withdrawal of PLO forces in eastern and northern Lebanon. There was no immediate confirmation of the report.

Lebanese officials initially had been buoyed by Habib's return to Lebanon yesterday from a tour of Arab and European capitals, as well as his success in arranging the conflict's seventh cease-fire to end the heaviest Israeli air, land and sea bombardments of West Beirut since the siege began.

Then, however, the mood turned skeptical today when few solid indicators of progress emerged from talks between Habib and Lebanese negotiators, on one hand, and between the Lebanese and PLO officials on the other.

"I don't think we have made much progress," said normally optimistic former prime minister Saeb Salam, a key channel between the PLO and Habib. He said that little had changed since Arafat signed the document July 3 agreeing in principle to take his forces out of Lebanon, subject to certain conditions that Israel has found unacceptable.

The Jeddah update of that statement came in the form of a text issued by Secretary General Chadli Klibi of the Arab League, which established the committee including foreign ministers or representatives of Lebanon, the PLO, Syria, Kuwait, Algeria and host Saudi Arabia.

Klibi said the committee reached "complete accord" on the necessity of the PLO announcing "a decision to move its armed forces from Beirut and define guarantees for this move, along with guarantees to be worked out between the Lebanese government for the security of the refugees."

The committee also pledged to work for "lifting the siege of Beirut and its suburbs through a pullback of Israeli forces" and called on all Arab states "to pursue action for halting the Zionist aggression on Lebanon" through "direct efforts on international and other levels."

At the United Nations, PLO representative Zehdi Labib Terzi quoted the Jeddah communique as saying, "The Palestine Liberation Organization announces its decision to move its armed forces from Beirut," United Press International reported.

"The safeguards and guarantees for this move as well as the safety of the refugee camps will be determined in an agreement between the Lebanese government and the PLO in Beirut," he continued.

Palestinian leaders, discussing Habib's week-long tour of Syria, Saudi Arabia, Egypt, Israel, Italy and Britain, "are not in the least excited by what Habib came back with," said a PLO official.

According to Lebanese government sources, Habib reported that Syria, Egypt, Jordan and Iraq had agreed in principle to receive some PLO guerrillas and that Israel had promised to withdraw from the Beirut-Damascus road to permit the fighters' exit from Lebanon.

In another version of Habib's talks, the leftist newspaper As Safir reported that the U.S. envoy proposed that Syria and north Lebanon be used as initial staging points for a Palestinian evacuation and that the multinational force deploy in Lebanon as the guerrillas depart. The paper, which is close to the PLO, said Habib wanted this to happen by the beginning of August.

While refusing to discuss the substance of what Habib told the Lebanese negotiators, a well-informed Cabinet minister said "Habib is stressing the 'yes' but hiding the 'buts' " when it comes to the willingness of the Arab countries to receive the evacuated guerrillas. The minister said Egypt wants to tie receiving the Palestinians to an overall Middle East settlement; Jordan would take in only those unlikely to cause trouble, and Syria demanded a written request from Arafat to avoid any recriminations from other Arab countries.

On the other hand, a PLO official indicated that some progress had resulted from Habib's tour because, he said, the U.S. envoy was reporting that Israel had accepted the principle of a disengagement of forces and the entry of international peace keepers into Beirut.

A close adviser to Arafat, Hani Hassan, said tonight that he was "very optimistic" about the eventual outcome although he said that Habib had not brought back any new plan to solve the crisis.

"I think we will begin in a way to see the Israelis leave Lebanon," Hassan told reporters.

[Reuter quoted Lebanese government and Palestinian sources as saying that Arafat had outlined a plan to Lebanese Prime Minister Shafik Wazzan Thursday night to withdraw his forces to four Arab countries.]

[Arafat told Wazzan that up to 5,000 of the estimated 6,000 fighters could go to Egypt, Syria, Iraq and Jordan, the sources said.]

As the up-and-down negotiations continued to produce contradictory signals about progress toward a political settlement, the mood among PLO fighters deployed in the battle zones in West Beirut's southern suburbs seemed to be hardening. Having so far withstood the Israelis' overwhelmingly superior firepower longer than any Arab country in a previous Arab-Israeli war, the fighters appeared to be in no mood to make concessions.

Asked about the prospect of leaving Lebanon for other Arab countries, several expressed incredulity at the question.

The only cease-fire violation reported by the Israelis today involved a few mortar rounds from the PLO-dominated southern suburbs near the airport. There was no Israeli return fire.