A major confrontation between warring Christian and Moslem Druze militiamen was averted today when Druze militiamen released the Maronite Catholic archbishop of Tyre four hours after abducting him.

After direct appeals from Lebanese President Amin Gemayel and other political and religious leaders, Archbishop Josef Khoury, who was kidnaped on the outskirts of Beirut along with his driver and held in the nearby Druze village of Shuwayfat, was freed.

The kidnaping came after a weekend of violence during which more than 100 persons were abducted by the rival sects and as many as 35 of them killed.

Late tonight, Israeli authorities who mediated between Christians and Druze in the Chouf mountains overlooking Beirut said a prisoner exchange, including about a dozen of the dead, had begun, but there were no reliable figures on the number of hostages released.

Earlier today, a Druze militia force of about 20 was involved in a brief firefight with a platoon of the Lebanese Army, apparently as the Druze attempted to kidnap Christian workers at a canning factory.

Marine Maj. Fred Lash said that when militiamen attempted to charge the canning factory, frightened workers fled to the joint Marine-Lebanese Army checkpoint about 200 yards away asking for help. The Lebanese responded by sending two armored personnel carriers to the factory. After a brief exchange of fire, 16 Druze militiamen were arrested by the Army. No Marines were involved in the firefight.

The weekend violence erupted after a Druze clergyman was killed Saturday in a land mine explosion. The Progressive Socialist Party, which fields Druze militia, accused Christian militia of planting the mine, and said Christian snipers prevented relatives of the dead man, Sheik Rafik Ghannam from recovering his body.

The bodies of nine Christians and 14 Druze who had been kidnaped were found by Israeli soldiers. Kidnapings and slayings have long been part of the peculiar rules of civil war as practiced in Lebanon, most often involving civilians who happen to be in the wrong place at the wrong time.

Earlier this year, a reporter spoke to a Druze commander who condemned the practice even as he acknowledged his men were kidnaping Christians in retaliation for what they said were kidnapings of Druze by Christian militiamen. Asked why he allowed his men to continue the abductions, the commander shrugged and said that while he did not not like it, the Christian hostages would be needed to bargain later for prisoner exchanges.

But the slaughter this weekend was unusual even by the bloody standards of the Chouf where more than 200 other people have been killed in on-again, off-again sectarian battles since the Israeli invasion last summer.

Israel, whose troops occupy much of the Chouf, has taken something of a mediating role in the disputes, arranging cease-fires that invariably break down. The last previous big battle in the mountains had been two weeks ago. It spilled into the capital and its suburbs with shells from the Chouf pounding both Christian East Beirut and predominantly Moslem West Beirut.