The Israeli Army continued its withdrawal from southern Lebanon today, evacuating the port city of Tyre and surrounding Shiite Moslem villages that have been the center of resistance to the Israeli occupation.

As Tyre residents cheered and waved flags, Israeli units pulled out of the city late this morning, retreating south to a new line along the Lebanese coast about six miles north of the Israeli border.

The pullback from the Tyre region left the Israeli Army within the confines of a so-called "security zone," a meandering strip of Lebanese territory that runs parallel to the border from the coast to a point about five miles north of Hasbaya in eastern Lebanon.

Israel is expected to evacuate the security zone sometime next month, ending its direct involvement in Lebanon that began with the June 1982 invasion. However, officials here have said that even after the final withdrawal to the border, Israeli units will continue to man "temporary outposts" and conduct regular patrols in the security zone in support of Israeli-backed local militias.

The latest Israeli pullback came amid statements by civilian and military officials that Israel will not be drawn back into Lebanon to assist Lebanese Christian forces that have been routed in recent days by a combination of Druze, Moslem and Palestinian militias.

Thousands of Christian refugees have fled from the villages east of Sidon, an area evacuated by the Israelis on Feb. 16, to the Christian town of Jezzin, from which the Israelis withdrew last week. Others have made their way as far south as Marjayoun, which is within the Israeli security zone and is expected to remain under Israeli protection even after the final withdrawal.

Despite Israel's longstanding alliance with the Lebanese Christians, Israeli officials made clear that their bitter, three-year experience in Lebanon had left them with no inclination to come to the rescue of the Christians.

"We have decided to put an end to our involvement in domestic Lebanese problems," Defense Minister Yitzhak Rabin said in Tyre. "I believe it is time for the Christian world, especially Europe, to show up whenever the Christians are in real danger. For the last three years, we have heard cries for Israel to leave Lebanon. Let the Europeans enter now and save the Christians."

According to military officials, while Israel is firmly opposed to intervening in the internal Lebanese fighting, it has supplied food, medicine and other nonmilitary supplies to the Christians in Jezzin. Rabin also said Israel will defend any Lebanese sect within the security zone because that territory is considered "essential for the defense of Israel."

Today's pullback followed a pattern that has become familiar during the prolonged Israeli withdrawal from Lebanon. As columns of tanks and other vehicles moved south and east into the security zone, Israeli warplanes and helicopters showered the area with leaflets warning residents not to continue their attacks on Israeli units.

"The long hand of Israel sooner or later will reach those who dare to act against its soldiers and citizens within the evacuated territory," one of the Arabic-language leaflets said.

After the pullback, Lebanese Army soldiers, members of a handful of units that have remained in southern Lebanon, and militiamen from the Shiite Moslem militia Amal entered Tyre, where they were greeted by celebrating residents.

"Life under the Israelis turned Tyre into a big jail," one man told reporters. "It was a big prison, but now, thank God, it's over."

The departing Israeli soldiers appeared to be at least as happy that the occupation had come to an end. Tank crews decorated their vehicles with balloons and one tank bore a sign that said: "Goodbye Lebanon, a country that consumes its occupiers."

There were no reported incidents during the pullback. Timur Goksel, the spokesman for the U.N. force in southern Lebanon, said that the Amal militiamen and Lebanese Army soldiers were working together and that local Amal leaders had pledged to cooperate with the U.N. units.

Goksel said the initially smooth transition appeared to have been aided by a radio statement yesterday by Nabih Berri, the Amal leader and a minister in the Lebanese Cabinet, calling on the militias to cooperate with the U.N. force.

Amal has been in the forefront of attacks on Israeli units, especially in the Shiite mountain villages east of Tyre. However, Maj. Gen. Ori Orr, the Israeli Army's northern commander, predicted that with today's pullback to the security zone, the Shiite attacks on Israeli targets will subside.

The security zone area that remains under Israeli control covers about 325 square miles -- 8 percent of Lebanon's territory -- and has a population of about 115,000, according to Israeli Army figures.