BEIRUT, Lebanon (AP) _ The commander of Lebanon's main air force base was assassinated on Sunday and his son was seriously wounded by a carload of gunmen who sprayed his private car with automatic rifle fire.

In other violence in Lebanon's 10-year-old civil war, new Moslem-Christian fighting broke out in the divided capital, Shiite Moslems pressed Palestinians trapped in refugee camps on Beirut's outskirts and hostilities from both conflicts spilled over into the south.

The Shiites are determined that the Palestinians will not rebuild their power base in Beirut which was crushed by the Israeli invasion in 1982.

Police said at least two people were killed and 18 were wounded in overnight skirmishes that strained a ceasefire called by the Shiite militia Amal and observed by the Palestinians on Friday night.That raised the known toll in the camps war to 502 killed and 2,063 wounded, by police count.

The killers of Col. Suleiman Daoud Mazloum, Christian commander of the air base at Riyaq, in the Bekaa Valley, sped away after the attack. The assault occurred in the village of Ablah in the Bekaa, in Syrian-controlled east Lebanon, an area populated mainly by Shiites.

The identity of the gunmen was unknown.

Lebanon's air force lakcs serviceable aircraft.

The two-week-old Shiite-Palestinian war spread to south Lebanon on Sunday when Amal militiamen swept into the Al-Bass refugee camp near Tyre, 40 miles south of Beirut.The Amal raid came after Palestinian guerrillas in the camp opened up with automatic rifle fire on an Amal checkpoint at the camp's entrance, reporters on the scene said.

Amal men took away five gunmen and weapons from the camp. No casualties were reported in Al-Bass, which has an estimated population of 10,000.

Tension rose in the Ein el-Hilweh camp outside the southern port of Sidon after Palestinians began fortifiying it.

An International Red Cross team brought 29 wounded from the sprawling Bourj el-Barajneh camp in south Beirut on Sunday and rescuers said many others remain trapped inside. Red Cross teams have evacuated 95 wounded in three missions.

Amal militiamen dragged two wounded men from the ambulances, ripping off their bandages to make sure that they were hurt, not fighters trying to escape.

One of the Palestinians, Mohammed Sleiman, 33, was dragged out twice before the six ambulances reached a hospital in the Druse-held Shweifat district.

''I was very lucky,'' he told reporters. ''One of the Amal fighters recognized me. He used to be a friend of mine. He made them let me go.''

Sleiman, shot in the hand early Sunday, said hundreds of Palestinians had been killed in Bourj el-Barajneh since Amal launched its assault May 19.

''They're digging pits for mass graves,'' he said. ''They put 20 or 30 bodies in the graves. Things are very bad. There's no water. The children are dying.''

Police said 40 bodies were recovered from nearby Sabra and Chatilla camps Saturday night.

The committee that runs day-to-day affairs in the camps appealed Sunday to Arab leaders and international relief agencies to intervene to ''save lives.''

A Popular Committee statement said: ''There are hundreds of wounded. Scores of wounded have bled to death and the children are dying of hunger and of disease. Houses are being blown up and set ablaze and hundreds of civilians are being seized.''

Palestinian spokesmen Saturday said disease was spreading in the camps, including what they believed to be cholera.

Palestinian spokesmen reported no major assaults Sunday, but said the Shiites were ''nibbling away at our positions little by little'' with automatic weapons fire and grenades.

Police said Christians and Moslems fought with grenades and anti-aircraft guns along the Green Line that splits Beirut into Christian and Moslem sectors, with two people reported killed and seven wounded.

In south Lebanon, radio stations said Israeli-backed South Lebanon Army militiamen and Moslem fighters fired artillery and mortar rounds at each other for two hours Sunday around the Christian mountain town of Kfar Falous, east of Sidon.