Dead Hold Secret of Undeclared Yugoslav War : Toll: The nation’s Defense Ministry reports only 400 fatalities. Croatia admits to more than 2,000 on its side.

From this hilltop village overlooking the grimy outskirts of Belgrade, a concrete latticework stretches across a wind-swept slope, marking out hundreds of new grave sites for the victims of Yugoslavia’s undeclared war.

Dozens of the freshly poured frames at Lesce Cemetery are already filled with the coffins of teen-age soldiers and mounded with dirt. A wood cross stands in for a headstone. Aluminum figures spell out the departed’s name.

Some of the crosses are marked “N. N.” in Cyrillic letters, an abbreviation for identity unknown. Yet victims such as C184 and C200--nameless bodies buried at Lesce--are discernible as war casualties by the red-ribboned wreaths laid by the federal army.

How many of Serbia’s young men have died in four months of war with neighboring Croatia is a carefully guarded secret masked with an official lie. The Yugoslav Defense Ministry reports 400 dead soldiers, yet recruits deserting the ragged front in droves say that hundreds die each day.

Belgrade residents who have recently lost loved ones say that morgues and funeral homes throughout Serbia are filled to overflowing. Peace activists and the parents of men missing in action shudder amid reports of untold hundreds of dead from both sides left on Croatia’s battlefields.

Croatia admits to more than 2,000 fatalities on its side, and a senior official said Sunday that the overall death toll is more than 5,000.

Croatian Foreign Minister Zvonimir Separovic cited the figure in a letter to European Community foreign ministers, appealing for “urgent economic and humanitarian aid.”

Officials in both warring republics say the Serbian-led army has suffered the brunt of recent casualties because federal soldiers are the outsiders attacking determined Croats defending their homes.

Physical evidence of the war’s cost is mounting, belying the official reports.

The back pages of newspapers such as Politika, Belgrade’s main daily, are filled with funeral notices and black-bordered messages of final regards to army “volunteers.” On any given day there are a dozen youthful victims just from the capital, which has sent proportionally fewer of its young men to the front than have provincial regions of Serbia.

“The sad truth is that no one--not even the army--knows how many have died in this pointless war. But I wouldn’t say more than 10,000,” estimated Milos Vasic, a Serbian journalist with the unofficial weekly magazine Vreme.

In nearly two months of intense fighting around Vukovar, a town in eastern Croatia, an average of 100 to 150 federal army soldiers have been killed each day, said Vasic, who compiles his figures from checks with morgues in the republic of Serbia.

“One soldier told me there were 93 men killed in one day’s fighting around Vukovar just from his own unit,” said a volunteer medical worker in Belgrade, who did not want to be named.

Getting at the truth of the war’s death toll is fraught with complications on both sides of the front.

The federal army and Serbia’s Communist leadership, seeking to hide the war’s human costs from a traumatized public, have deliberately understated the casualties on their side.

The cover-up has spurred rumor and exaggeration, with unconfirmed reports that Serbian fighters are secretly burying their dead in mass graves in Croatia or transporting the bodies back home at night for quiet interment in unmarked graves like those at Lesce.

Yet only half a dozen of the most recent burials at Lesce bore the anonymous designation “N. N.”

Croatian authorities, conversely, have often sought to overstate the Serbian losses, partly to inspire Croatia’s national guardsmen by creating an impression that the war is turning in their favor.

In the first weeks of fighting after Croatia declared independence on June 25, Serbian guerrillas backed by the federal army seized more than one-third of Croatia’s territory.

Some reports from Zagreb have claimed 16,000 dead among Serb irregulars and the federal army, but Belgrade routinely dismisses those figures as propaganda.

Dr. Ivica Kostovic, dean of the University of Zagreb’s Medical School, estimates that 2,000 have died on Croatia’s side but contends that the Serbians’ losses are much higher because they are attacking in unfamiliar territory instead of defending what is their own.

Kostovic said he is disturbed by reports that the Serb guerrillas occupying broad swaths of Croatia have left the corpses of their fellow irregulars unburied in the empty front-line villages from which most residents have fled.

“They leave the bodies in the mud for days or months. There is already disease” from the decomposing bodies, Kostovic said.

Croatian forces and the Yugoslav army return their dead to the families back home, but Serb guerrillas roaming from battle to battle without clear supervision or support have no means of dealing with their losses.

The Serb militants, who have been aided in their territorial seizures by the tens of thousands of federal troops deployed in Croatia, now control huge areas that were the scenes of major battles, where Zagreb authorities fear many of their national guardsmen lie dead.

“The real number of dead will be counted long after the war,” said Zarko Mahovic, a spokesman for Croatia’s Defense Ministry.

Meanwhile, the funeral parlors and graveyards in both republics fill with visions of sorrow.

A virtual caravan of coffins moves across the hilly Lesce Cemetery on weekends, with tearful friends and wailing mothers accompanying the remains of their loved ones to a final resting place in the concrete maze.

“It’s hard for everyone when they lose their children,” said Mladen Pezelj, a civilian mortician for 18 years before taking on the task of burying fallen members of the Croatian national guard.

“This is only young men,” said Pezelj, whose hearse marked with a red cross has been fired on while retrieving victims. “In civilian life, there were old men, old women.”

While the reality of the war’s human damage is dawning on thousands of families who have lost a husband or father or son, the gross distortions of the death toll promise to confuse many others and only intensify their determination to fight.

Western diplomats--who put the likely death toll between 3,000 and 8,000--contend that both sides will have to honestly disclose the losses suffered before their populations can end a conflict that all agree no one will win.

Special correspondent Danica Kirka in Zagreb contributed to this story.