Rebellion against the leadership of Yasser Arafat has broken out among the ranks of the Palestine Liberation Organization guerrillas in eastern Lebanon's Bekaa Valley, according to several reports reaching here.

According to the still sketchy accounts, there have been recent battles in the Bekaa between PLO elements supporting and opposing Arafat and on one occasion a sit-in demonstration there to protest his continuing leadership. Arafat went to the area Friday and yesterday, reportedly in an effort to resolve the dispute.

The reports came as Israeli and Lebanese negotiators, meeting in Netanya, Israel, reached agreement on a final text of a U.S.-sponsored plan for withdrawal of Israeli forces from Lebanon. Israeli radio said the agreement will be signed on Tuesday.

It was not immediately clear whether the apparent dissension in the ranks of the PLO would further complicate the situation in Lebanon or affect efforts to gain agreement for the withdrawal of Syrian and PLO forces, a condition for Israeli withdrawal.

Syrian President Hafez Assad has sharply attacked the Lebanese-Israeli accord, and today Arafat condemned it. The PLO chairman called on his forces to prepare to wage war against Israel and the United States, according to the PLO news agency Wafa as quoted by The Associated Press from Damascus.

"An effective war is the only way to redraw the political map of the Middle East," Arafat told members of Fatah, his faction within the PLO. "The way out of this present deadlock is taking a decision to wage war to change the balance of power," Arafat said, urging his followers to battle the "Zionist-American enemy."

Often in the past Arafat has made strong anti-Israel speeches to firm up his position within the PLO, where his leadership frequently has been challenged by more radical factions.

Arafat's recent negotiation with Jordan's King Hussein over President Reagan's Middle East peace initiative appears to be one cause for the reported opposition by an undetermined number of his forces in the Bekaa. Hussein broke off the talks, accusing Arafat of reneging after reaching virtual agreement on a joint approach.

Another reported reason for the dissension is lingering hostility from last summer when Arafat agreed to the evacuation of PLO forces from Beirut.

Arafat went to the Bekaa last night, reportedly in an effort to quell the rebellion. On Friday he had gone there for his first visit to Lebanon since he was evacuated from Beirut last September.

His deputy, Khalil Wazir, also known as Abu Jihad, told reporters when he and Arafat returned to Damascus early this morning that the problems had been "settled" and that they were in "full control of the matter."

But the official news agency of the Libyan government, which has lent encouragement to PLO dissidents and added attacks of its own against Arafat, insisted there had been a "revolution" within the ranks of fighters in Fatah, the largest PLO faction and Arafat's principal base of support. The Libyan agency said Arafat, in his visits, had been unable to reach positions controlled by breakaway Fatah members.

Last week, Libya said a Palestinian in Tripoli who had been previously allied with Arafat had confessed he had been assigned the duty of assassinating Libyan leader Muammar Qaddafi and had received instructions from the American Central Intelligence Agency.

Arafat supporters called the charge "nonsense."

Both the PLO and Syria, behind whose lines PLO guerrillas are deployed, have rejected the U.S.-sponsored accords for Israeli troop withdrawal, saying they amount to capitulation to Israel.

Lebanese President Amin Gemayel reportedly told religious leaders he met with here today that Israel has warned it will nullify the accords if Syria and the PLO are not out by a date to be set later.

Gemayel was described by state-run Beirut radio as saying this was why the religious leaders' support for the accords was critical. In addition to attempting to build a national consensus for the peace agreement, the Lebanese president sent an envoy to the moderate states of the Persian Gulf seeking support.

Beirut radio also said Algerian President Chadli Benjedid told Gemayel in a telephone conversation last night that he "stood behind Lebanon and its president."

Syria continued its attacks on the accords, warning today that if they are signed, a new civil war could break out in Lebanon.

Last week Assad sent envoys to Lebanese political leaders who oppose the agreement with Israel. Yesterday a group of them formed a "national front" to resist the agreements.

Al Baath, the official newspaper of Syria's ruling Baath Party, said today that Syria would give all possible support to efforts inside and outside Lebanon to defeat the agreement and called for "escalation of national struggle."

Arafat moved to repair a months-long rift with Syria earlier this month after the collapse of his talks with Hussein. On May 3 he held his first meeting with Assad since the evacuation of PLO fighters from Beirut. At the time of the evacuation, Arafat criticized Syria for failing to come to the PLO's defense in the Israeli siege.

This month Arafat has spent most of his time in Damascus, holding rounds of meetings with PLO leaders opposed to the talks with Hussein and with members of the various military commands in the PLO.