WASHINGTON (AP) _ In two days of bombing, U.S. and allied warplanes virtually shut down Bosnian Serbs air defenses and helped silence the artillery guns that had terrorized Sarajevo. But the destruction was far from complete, according to U.S. and NATO officials running Operation Deliberate Force.

Partly by design and partly due to bad weather, the air assault was limited in scope and intensity, even before NATO's decision Friday to suspend the bombing.

It had the effect of stunning, not defeating, the Serb military, analysts said.

Heavy guns fired by U.N. soldiers in the Sarajevo area kept blasting away at Serb artillery emplacements Friday while NATO aircraft kept watch from above. It was an artillery shell fired into a Sarajevo marketplace on Monday, killing 38 people and wounding many more, that triggered the allied air attacks.

Deliberate Force began at 2 a.m. Wednesday (8 p.m. EDT) and was suspended before dawn Friday Bosnia time after roughly 500 strike and support missions.

The Serb artillery was not a top priority target of the NATO warplanes, which directed their bombs initially at the Serb air defense network that links radars and fire-control centers with mobile and fixed ground-to-air missile launchers. Command centers and communications facilities such as telephone switching stations also were among the targets in the early hours of bombing.

That cleared the way for the NATO aircraft to operate with less risk of being shot down.

The campaign against the Serb air defense system was designed to ``suppress'' it, not necessarily to destroy it, British Air Force Group Capt. Trevor Murray told reporters Friday in Naples, Italy. Murray is chief of the air branch of NATO's southern Europe headquarters, which is running the air campaign.

As evidence that this goal had been achieved, Murray said NATO pilots had faced no threats from Serb surface-to-air missiles Thursday and there had been no further instances of shoulder-fired anti-aircraft missiles being fired. It was a shoulder-fired missile that knocked a French fighter out of the sky Wednesday.

The Serb defenders mostly chose not to activate their aircraft tracking radars in order to avoid getting shot at. So the Serbs could, theoretically, use the air defense system again later, although they would risk losing it so long as NATO planes stayed on patrol. That's the kind of success NATO was looking for.

``We have had a measurable effect on those targets,'' Murray said, ``so we characterize the operation as successful.''

In addition to paralyzing the air defense system, the NATO planes struck at large ammunition depots, a military radio station, repair facilities and other targets that supported the Serbs' ability to carry out military operations. In all, 25 targets were bombed; an exact damage assessment was not yet available.

While some Serb artillery was hit, much of it was moved into hiding _ another example of silencing the Serb weaponry without actually destroying it.

``We have completely suppressed in our opinion the ability of the Bosnian Serb heavy weapons to fire back into Sarajevo,'' said U.N. spokesman Lt. Col. Chris Vernon.

He acknowledged that most Serb weapons had only been moved from their firing positions into the woods, ``which makes it extremely difficult for us to target them.''

Col. James Cartwright, commander of the two Marine Corps F-18 fighter squadrons that are flying in Bosnia, said in a telephone interview Friday that NATO planes had attacked Serb artillery only enough to keep them from shelling Sarajevo.

Military analyst Harry Summers Jr. said he believes the physical destruction wrought by the NATO attacks was less important than the psychological effect the show of force had on the Serb leaders.

``The air attacks are evidence that we finally have the backbone to do something to end this war'' and that probably had more to do with the Serbs agreeing to peace talks in Geneva than the bomb damage itself, said Summers, a retired Army colonel.