BEIRUT, Lebanon (AP) _ Vicious shelling across this embattled city killed eight more people before dawn today but then subsided long enough to allow rescuers to begin evacuating 70 wounded Moslem civilians to a French ship.

Pillars of flame from blazing buildings seared the darkness overnight while Christians and Moslems pounded each other's areas with artillery and rockets in a nightlong blitz.

In addition to the overnight deaths, police reported 43 wounded as the divided capital's population huddled in underground bunkers and bomb shelters for a third straight night.

President Francois Mitterrand of France contacted President Bush and several other world leaders today to solicit help in ending the civil war, said presidential spokesman Hubert Vedrine in Paris.

Vedrine said Mitterand also contacted Prime Minister Margaret Thatcher of Britain, President Chadli Bendjedid of Algeria and Egyptian President Hosni Mubarak.

The latest casualties raised the toll from six weeks of fighting to at least 270 killed and 975 wounded, mostly civilians. By police count, 53 people have been killed and 218 wounded in almost non-stop artillery and rocket exchanges since sundown Saturday.

The bombardment slackened at daybreak into intermittent exchanges between mainly Christian army units loyal to Gen. Michel Aoun and an alliance of Syrian troops and Moslem and Druse militiamen.

During the lull, rescue teams assembled the 70 wounded Moslems in Moslem west Beirut near the home of acting Prime Minister Salim Hoss, who heads a Moslem Cabinet vying for power with a rival Christian government.

On Saturday, the French navy hospital ship Rance evacuated 14 wounded Christians from the port of Jounieh, north of Beirut.

This morning, a Lebanese vessel, the Ibrahim, left the port of Sidon 25 miles south of Beirut with 35 of the wounded civilians and some relatives.

Jamal Dousouki, a wounded rescue worker, was accompanied by his sister Sawsan. He said he was maimed Sunday when a shell exploded in west Beirut near an ambulance he was riding in.

The explosion ''hurled me and my colleague, Mohammed Rustom, out of the ambulance .... I lost my leg and Rustom was seriously wounded. I was screaming for help, but there was nobody in the street,'' he said.

''Rustom crawled to me. He had enough strength in him to drag me to the ambulance. He started it and drove slowly. He was bleeding all the time. Shortly after we reached hospital, he passed away,'' Dousouki said, his eyes brimming with tears.

Mustafa Itani, 20, another rescue worker who lost his left leg and eye in the shelling last week, was in shock. To each question, he replied only, ''I don't know.''

The wounded were escorted by France's minister for humanitarian assistance, Bernard Kouchner, and French Ambassador Paul Blanc. The French ruled Lebanon until 1943.

The Lebanese ship was to make a second trip later in the day to evacuate another 35 wounded Moslems, including 10 civil defense workers, said Dr. Kamal Mohana Mohanna, a public health adviser to Hoss.

Mohanna said the evacuees will be flown from the Rance to ''hospitals in France for proper treatment.''

The Lebanese ship was to return to port with medicine.

Kuwait's foreign minister called Monday for an emergency meeting of the Arab League to discuss the fighting. The foreign ministers of the 22-member league would meet at group headquarters in Tunis, Tunisia, but no date has been announced.

The nightlong barrages escalated sharply around midnight, minutes after Aoun declared in an interview with the Christian Voice of Lebanon radio station that his forces would crush President Hafez Assad of Syria.

''Lebanon will be his graveyard and that of his regime,'' Aoun boasted, even though his forces are outnumbered by at least 3-1.

The independent An-Nahar daily quoted Druse warlord Walid Jumblatt, Syria's main ally in the current fighting, as saying it was impossible for Aoun drive the Syrian army out of Lebanon.

Syria, the main power broker in Lebanon, maintains about 40,000 troops in Lebanon under a 1976 Arab League mandate.

The current fighting broke out March 8 after Aoun, who heads the Christian Cabinet, ordered a blockade of militia-run ports. It was part of his effort to restore state authority, which has eroded during 14 years of civil war.