Rebelling Christian militiamen seized the last position in east Beirut held by forces loyal to President Amin Gemayel today and said their goal is the removal of Gemayel as leader of Lebanon's main Christian party. Syria issued a new warning that it will not remain "indifferent" to the rebellion.

The Christian militiamen, called the Lebanese Forces, angered at growing Syrian influence in Lebanese government affairs, marched on the position in east Beirut's Karantina neighborhood and routed the Gemayel loyalists without any reported causalties in a 45-minute shootout. Two persons were reported killed in an earlier clash in east Beirut.

The Syrian warning to the rebellious militia, which numbers about 6,000, linked the revolt to Israel, saying that Syria could not remain indifferent to what the official Syrian news agency, SANA, quoted official sources as calling "a suspicious move linked to the Israeli enemy."

SANA quoted the sources as saying the actions of Lebanese Forces Commander Samir Geagea, leader of the rebellion against Gemayel, are aimed at toppling the Syrian-backed "national unity" government and partitioning Lebanon.

Against the backdrop of the Syrian warning, a senior official in the breakaway militia said today that the rebels want to avoid provoking Syrian President Hafez Assad into intervening and instead want to negotiate a settlement with Gemayel.

Emile Rahme, a top aide to Geagea, said in an interview that the Lebanese Forces are content to have Gemayel remain president as long as he gives up leadership of the Phalangist Party. He said Geagea had stated that position at yesterday's mediation session.

"He [Geagea] said that Amin Gemayel has to choose between the presidency and the leadership of the party. This movement is not against the presidency. It is against the leadership of the party." The Lebanese Forces long have been demanding what they call independence of Christian decision making and an end to Syrian power broking in efforts to negotiate a political accord between Christians and Moslems.

Rahme said Geagea was aware of Syria's concern over its interests in effecting a political settlement in Lebanon, but is convinced a confrontation is unnecessary.

"If we become a danger to Assad, he has to do everything to stop us. Until now, I would do exactly as he has. But this movement is for returning rights to the Christians, and it is not against Syria. I don't think they will do anything because I don't think Syria wants a non-Christian decision," said Rahme, a confident of Geagea who has participated in talks between the rebel commander and mediators seeking a compromise solution to the crisis.

He added, "Now we are telling Mr. Khaddam [Syrian Vice President Abdel Halim Khaddam] we want to negotiate a settlement. We don't want to kill anybody. This movement is not against Syria at all."

For their part, Lebanese government leaders met today in Damascus with Khaddam to discuss the crisis. Attending were Prime Minister Rashid Karami, Shiite Amal movement leader Nabih Berri, Druze leader Walid Jumblatt and Sunni Moslem politician Salim Hoss.

The Syrians, while increasingly concerned about the split between the Phalangist Party and the Lebanese Forces militia, appeared intent on reaching a negotiated settlement and avoiding direct intervention.

While the militia would be no match for the Syrian Army, military action would almost certainly rally most of Lebanon's Christian community around Geagea, a charismatic leader who had close ties to assassinated Lebanese president Bashir Gemayel, brother of Amin Gemayel.

The regular Lebanese Army also outnumbers the Christian militia, but it is questionable whether its Christian-dominated officer corps would move against Geagea.

"The majority of the officers are not against us, and they won't agree to fight us. A Christian soldier won't agree to kill Christians," said Rahme.

The confrontation between the Christian militia rebels and Gemayel and the Phalangist Party, however, has broad implications for the future of the Syrian-engineered efforts to stabilize the Lebanese government and apportion representation between Christians and Moslems, and for the future of the Phalangist Party, which, without a militia, would be vastly weakened.

"We are the party now," said Rahme, adding that the Lebanese Forces' long-range goal for Lebanon is a confederation providing military autonomy for the Christian areas of the country.

Breakaway militia commanders formed an "emergency committee" to lead the rebellion, including Geagea and Elie Hobeika, who was linked to the 1982 killings of Palestinians at the Sabra and Shatila refugee camps.