US role in Beirut goes on despite exit of marines from peace force

American involvement in Lebanon diminished dramatically Sunday with the final pullback of the Marine contingent in the multinational force to Sixth Fleet ships offshore. Thus ended a 17-month presence that did not appear to help solve any of the country's many problems.

Yet the continued United States commitment to Lebanon - at least at a safe distance - was underlined when the USS New Jersey battleship opened fire within 40 minutes of the Marine withdrawal at targets behind Syrian lines in the mountains surrounding Beirut. It was the second time in less than 24 hours that US warships bombarded positions that were firing on US targets.

The last 1,000 troops of the 22nd Marine amphibious unit rolled out on a day marked by violence despite a series of cease-fires declared over the weekend. No political solution appeared in sight in spite of Saudi-mediated negotiations.

Fighting between the Lebanese Army and Druze militia in the nearby Shouf mountains provided a noisy backdrop to the Marine evacuation. One officer commented: ''This ceasefire is getting louder.'' The artillery, rocket, and machine-gun exchanges, usually limited to the ''green line'' that divides the Christian and Muslim sectors of the capital, spilled over into suburbs of east and west Beirut.

The general pessimism about the US military mission was expressed by Lt. Peter Walton, who rolled out with one of the five massive M-60 tanks shortly after dawn: ''If (the Lebanese) wanted peacekeepers, they should have wanted peace. The only peace I saw was them shooting at each other.''

Gunnery Sgt. Michael McGilveray expressed a tinge of bitterness: ''No more wounded, no more killed. All these people want us to do is go home. Let them kill themselves.''

Shortly before the final departure at 12:37 p.m., Marine commander Gen. James Joy said: ''I do think that in 17 months we were able to give this small country a chance, some breathing room to try to regain control of the country, give their Army a chance to develop.''

But he also noted: ''I've said all along that I don't think the solution in Lebanon is a military solution. It's going to be a political solution. Hopefully , at some time, the people will say 'enough's enough,' and they will pull together as a nation.'' And he added about the residual US presence, which General Joy will stay behind to command: ''We, of course, have not given up. We'll continue to do what we can, as our President directs.''

But the divisions within Lebanon were symbolized by the fact the Marines were forced to turn over their compound around Beirut airport to units that defected from the Lebanese Army when west Beirut fell to Muslim militias three weeks ago, instead of official government troops the Marines came to Lebanon to support.

Within three minutes after the last of 10 amphibious personnel carriers splashed into the Mediterranean bound for the US ships, gunmen of the Amal Shiite Muslim militia took over the beachfront, hoisting their green and black flag over the former Marine observation-post tower, and deploying troops.

The pullback does not end the dangers to the US presence, as evident when antiaircraft positions behind Syrian lines fired Sunday at US reconnaissance planes streaking over the mountains. A Marine contingent of roughly 100 men will stay onshore to guard the two US diplomatic facilities. An estimated 70 US Army trainers also stay to help what remains of the Lebanese Army.

Although the US military commitment has been cut back, Washington clearly does not feel the mission is over. A new Marine contingent has already set sail from the US to relieve the force now deployed offshore.