Pulling Back From Heights, Serbs Report : Bosnia: But a withdrawal from mountains around Sarajevo may be mere ‘stage management,’ U.N. spokesman says.

On the eve of a key NATO meeting on air strikes in Bosnia-Herzegovina, Serbian forces claimed Sunday to be pulling back from heights above Sarajevo, but a U.N. spokesman said their maneuvers might be mere “stage management.”

Bosnia’s president, Alija Izetbegovic, claimed that the Serbs have been bluffing all along about a withdrawal. He called for urgent military action by the West to deter the Serbs’ purported intent to seek all-out victory in Bosnia’s civil war.

“One single air strike, it does not have to be big, would change the whole situation because it would prove to the Serbs that Americans mean business,” he said in Geneva.

The North Atlantic Treaty Organization is scheduled to meet today in Brussels to consider air raids on Serbian positions around the Bosnian capital. To forestall such attacks, the Serbs announced Thursday that they would pull their soldiers and armor off Mt. Bjelasnica and Mt. Igman, peaks controlling the southwestern entrances to Sarajevo.

Over the weekend, the Serbs moved a pair of tanks, some infantrymen and a few camouflaged vehicles off the wooded heights, but some feared that the moves may have been just for show.

“We hope that it is more than just clever stage management,” U.N. spokesman Cmdr. Barry Frewer said in Sarajevo. “We cannot confirm that it was fully a withdrawal.”

The Serbs want to hand the peaks they captured from Bosnia’s Muslims over to U.N. troops, a step that Izetbegovic’s government rejects on the grounds that it consolidates Serbian territorial gains.

The Serbian offer is also meant to draw Izetbegovic back to suspended talks in Geneva, where negotiators are considering a plan to slice up the former Yugoslav republic among its three warring communities: Serbs, Croats and Muslims. Those talks are supposed to resume today.

But Izetbegovic warned that the talks would collapse unless NATO intervened within days.

“I can say if there are no air strikes, then there is no peace process. No negotiations,” he said.

Also Sunday, Bosnian Serb leader Radovan Karadzic said his forces will open two roads into Sarajevo today to permit humanitarian aid convoys and commercial traffic. More than 300,000 people blockaded inside Sarajevo have endured appalling conditions for the last 16 months.

In Washington, meanwhile, a third State Department official resigned over differences with the Clinton Administration over its Bosnia policies, U.S. officials announced Sunday.

Jon Western, an analyst investigating war crimes accusations against Serbs in Bosnia, notified his superiors Friday that he is quitting in disagreement with a policy that he concluded was not tough enough, the officials said.

Western’s resignation follows the departure last week of desk officer Marshall Freeman Harris and the resignation last August of deputy officer George Kenney.

Their resignations reflect discord within the department over a policy that has not succeeded in stopping Bosnian Serbs from their assault on the Muslim population.

Special correspondent Laura Silber, in Geneva, contributed to this report.