DAMASCUS, SYRIA, OCT. 12 -- Lebanon's Christian rebel army commander, Gen. Michel Aoun, escaped a gunman's assassination attempt today as Syrian troops and tanks massed around his stronghold in the Christian enclave northeast of Beirut poised for an attack to oust him.

{Early Saturday, the Reuter news agency reported that Aoun also had escaped an apparent predawn attack on his headquarters by Syrian aircraft. "A squadron of Syrian warplanes . . . are bombing the palace and the defense ministry," Reuter quoted Aoun as saying over his radio station. He was later reported to have sought the safety of the French Embassy.}

The attempt to assassinate Aoun came as he was addressing hundreds of supporters who had camped around his shattered presidential palace at Baabda to shield him from attack by Syrian and Lebanese forces.

As he spoke, a young man wielding a pistol emerged from the crowd and fired two shots, missing Aoun but hitting one of his aides, Aoun's radio station said. The broadcast identified the assailant as an 18-year-old Shiite Moslem from the southern Lebanese town of Habboush and said the youth, who carries an Australian passport, had told military officials under questioning that he was ordered to kill Aoun, the Associated Press reported. The broadcast did not say who gave him the orders.

Reuter identified the youth, who was dragged away by security men, as Francois Halal and quoted sources close to Aoun as asserting that he was sent by the Lebanese Communist Party to kill the general. Five minutes after the incident, Aoun resumed his speech, telling followers, "This is an attempt to kill me and part of the plot aimed at my liquidation."

Today's was the first known assassination attempt against Aoun, who for two years has called himself the legal prime minister of Lebanon and has refused to accept the internationally recognized government of President Elias Hrawi, which is trying to end 15 years of civil war.

Hrawi's government has asked Syria for assistance in its drive to unseat Aoun unless he agrees to join the cabinet seated in mainly Moslem west Beirut. Syria, which has long maintained about 40,000 troops in Lebanon, is moving soldiers, backed by tanks and heavy artillery, to front-line positions. Lebanese army units commanded by Gen. Emile Lahoud, the appointed commander in Hrawi's government, continued today to take advance battle positions ringing Aoun's fortified territory.

Syrian officials and the Syrian media did not mention the events in Lebanon today, but security sources said that Aoun's removal was imminent. Aoun, who in recent months has lost some of his support in the enclave, vowed to fight and inflict heavy losses on his opponents "though the balance of forces is not in our favor."

Aoun told reporters that the massing of troops against him was either meant to press him into submission or intended for an assault. "We must take into account the worst, which is attack. In either way, we have one choice -- to resist and not to capitulate -- and we shall make this a tough confrontation," he said. "Everything is going to blow up in flames. I believe it's the final battle. But I'm prepared to resist whatever the outcome is. We don't have the choice. They've come to kill us," Aoun said.

Western diplomats in the Syrian capital expressed doubts that Syrian troops would intervene in the fighting at a time "when the Syrian leadership is criticizing Iraq for military action against another Arab country, Kuwait."

However, sources here said Hrawi's request for assistance gave Syria legitimate authority to intervene militarily in Lebanon. And the current participation of Syria in the U.S.-led alliance against Iraq in the Persian Gulf could now leave it with a freer hand than it has had in Lebanon.

Last year, Hrawi asked Syria for help in ousting Aoun, and Syrian artillery was deployed around the Christian heartland. There was no showdown, however, in part because Syria was believed to have feared Israeli reprisals and U.S. disapproval.

France made an urgent appeal today to all sides in the Lebanese war to avoid further bloodshed by honoring terms of an Arab-sponsored peace plan drafted in Taif, Saudi Arabia, last year. The accord called for a new power-sharing formula between Moslems and Christians in Lebanon, but Aoun rejected it because it did not contain guarantees for a complete Syrian military withdrawal from Lebanon.

Meanwhile, tank battles erupted between Aoun loyalists and rival Christian militiamen in three residential districts of Christian east Beirut. Residents scurried for cover as shells crashed into buildings at the rate of one a minute, Lebanese radio stations reported. There was no immediate casualty count from the latest battles for dominance in Lebanon's Christian heartland.