A Christian Lebanese leader yesterday vowed to "fight to the end" against Syrian peacekeeping forces and ruled out any compromise to end a weeklong conflict by saying that "the Syrians must get out" of Lebanon.

Camille Chamoun former Lebanese president and head of the right-wing National Leberal Party made the statement as diplomats here expressed fears that Syria and Israel were heading to ward confrontation caused by Syrian's bombardment of the Christian quarter of Beirut.

The statement also appeared to complicate Lebanon's internal political situation as President Elias Sarkis continued to dangle a resignation threat.

An underclared cease-fire, which took effect Thursday after Sarkis threatened to resign and Israeli jets buzzed Beirut, was holding into its second day. Last night a burst of shellfire, apparently fired from Syrian positions, hit the Christian suburb of Ain Rummaneh, but there were no reports of casualties.

Despite the unofficial truce, tension was high in Beirut yesterday. Israel's threat of intervention was seen here as a clear warning to Syria to stop shelling Christian residential districts in and around Beirut.

Starting July 1, the Syrians had unleashed a series of heavy artillery and rocket barrages against Christian quarters in an effort to tame the powerful militias of the National Liberal and Phalangist Parties.

In an interview with Western correspondents: conducted in a heavily guarded apartment in East Beirut, Chamoun said his party would make "no compromises whatsoever" with Damascus to solve the crisis.

"The Syrians have to get out," the 78-year-old former president said. "That's the only solution."

His son, Danny, the commander of the party's militia, called for the replacement of Syrian troops in the Arab peacekeeping force which has been responsible for security in Lebanon since its 1975-76 civil war.

"Something besides the Syrian army must be brought here," he said. "Anybody will be better than the Syrians."

Syrian troops, which stepped in on the side of the Christian rightists to end the civil war, comprise more than 90 percent of the 30,000 man peacekeeping force set up by the Arab League.

Phalagist Party leader Pierre Gemayel has stopped short of demanding the withdrawal of Syrian forces, but he and top party lieutenants have made it clear they are also unwilling to accept Syrian demands that the Christian militias be disbanded and their installations turned over to the peacekeeping forces.

In fact, both the Phalangists and the National Liberals, which muster combined forces of some 10,000 militiamen, appeared to have acquired a new confidence - even cockiness - toward the Syrians since Thursday.This has arisen from evident Syrian reluctance to see Sarkis resign or to fight Israel.

A Western diplomat called the uncompromising rightist stand "very unfortunate" and warned that it could be part of a chain of events culminating in a new Middle East confrontation.

A veteran diplomat said Christian reliance on the Israeli warning to Syria "only makes a political accommodation more difficult." He said such a situation might compel Syria to also adopt an uncompromising stance.

"It's not impossible that this is just what Israel wants," the diplomat said. "The Israeli solution to a problem seems to be to create another problem. And right now their main problem is that American public opinion is turning against them. A beautiful way to get out of this is to have another Middle East war."

He said Israeli threats to intervene against Syria in the Beirut fighting amounted to "a deliberate means of preventing a political accommodation here."

In the interview Chamoun said the issue of disbanding the Christian militia to help restore Lebanese government authority was "a Lebanese problem" that does not concern Syria.

"If not for the militias, we would have been crushed by the Palestinians and then by the Syrians," he said. "The moment we see that Lebanon is out of danger from the Palestinians and the Syrians, we are ready to agree with the Lebanese government about the militias."

The Christian rightists, who fought a Palestinian-Lebanese Moslem alliance during the civil war, insist on maintaining the militias for their own security in the absence of strong national army and police forces. But the government argues it cannot impose the authority of these forces as long as the militias remain so powerful.

Chamoun also said he has urged Sarkis to "accept his responsibilities as head of state" and remain in office.

Despite similar pleas from all quarters, Sarkis was refusing to withdraw his resignation threat in what diplomats said was a last-ditch effort to wring concessions out of both sides in the latest conflict.