GIBY, POLAND -- Discovery of a mass grave near the Soviet-Polish border has reopened a bitter chapter in Soviet-Polish relations and brought citizens into conflict with government officials over what the grave contains -- the remains of German soldiers killed in World War II or Polish villagers slaughtered by Soviet troops near the war's end.

Since the grave site was discovered June 29 after a resident of Giby said he had seen it in a dream, hundreds of Poles have flocked to it daily, many of them in the belief that relatives are buried there.

Three weeks ago, an official team opened the grave and found, it said, nothing but the remains and artifacts of Nazi soldiers.

The villagers of Giby were not convinced. Many remember that an estimated 180 Poles living in the Giby area disappeared in June 1945 during the Soviet occupation. They say that the investigation was inadequate, that the grave was closed too quickly.

"Of course" the bodies were Poles, said Marzena Milczarek, 32, who came to the site from Warsaw, 170 miles away.

"I have a brother, three uncles and four best friends buried here," said Stefan Milewski, a Giby veteran of World War II.

"It's all a cover-up," said his middle-aged son, Edward. "We need an objective commission to look into this."

Inflamed by such strong beliefs and passions, the Giby affair is already a national cause celebre that has prompted fresh accusations that Polish and Soviet authorities covered up one of the most bloodcurdling and embarrassing chapters in Soviet-Polish history.

It has magnified interest in a new Soviet-Polish commission, composed of historians and party officials and charged with filling in the blank spots of Soviet-Polish history -- incidents so controversial they have been left out of official communist history books on both sides of the border.

In a recent interview, Warsaw-based historian Eugeniusz Duraczynski identified some of those blank spots Poles are most anxious to fill in:The Soviet annexation of Lithuania, Latvia and Estonia in 1940. The deportation of more than 1 million Polish citizens to Siberia and other parts of the Soviet Union between the fall of 1939 and the spring of 1941. "We know the facts," Duraczynski said. "We would like to know more about the conditions under which the deportees were transported and lived."The internment of 10,000 Polish military officers in the Soviet Union in September 1939. Called the Katyn case, it is the most bitter of Soviet-Polish controversies, arising from the 1943 German Army announcement that Nazi troops had found thousands of Polish officers buried in Katyn, near the Soviet city of Smolensk. The case never has been explained in Soviet or Polish history texts.

"Polish people know the facts about these cases, even though they are ignored in the official propaganda," Duraczynski said, "but they want to see officials confirm what they already know in print and on the radio."

Soviet historians' continuing demystification of Joseph Stalin is a step in filling in the blank spots, Duraczynski said. "It adds to the understanding of what Stalinism really meant for Russia, and what it meant for the rest of Eastern Europe," he said.

Meanwhile, on the smaller scale of Giby and the grave site six miles away, mourners continued to arrive last weekend, convinced that missing relatives and friends and fellow countrymen are buried there.

Forester Jozef Wasilewski was one of them. He made his way down the dirt road leading to the grave, tucked away among pine trees and bedecked with flowers left by others.

Clutching a bunch of lilacs and fighting tears, he told a small crowd, "My brother is probably buried here. He disappeared 42 years ago from a field near here. He was only 19."

In Warsaw, government spokesman Jerzy Urban and other Polish officials dismissed assertions that a new rift had appeared in Polish-Soviet relations. Pointing to the German paraphernalia exhumed from the site, Urban said the discovery was "nothing but the old graves of Nazi aggressors."

Polish official investigator Waldemar Monkiewicz said at the same press briefing, "The things we found in the graves included identification signs, uniform buttons, a 'death's head' of the type worn by SS field officers, a cigarette case with German writing etched inside of it, parts of a military flag and suspenders worn by German soldiers."

In Giby, however, villagers stood at the grave and complained that Polish officials were too quick to close the case. Several called for an international team of investigators to reexcavate the whole area to prove that their missing relatives were not buried there after all.

One local man who visited the grave site reiterated the version published in the local party newspaper -- that excavators found 11 bodies of German soldiers when they opened the grave on July 16.

In response to rumors, the local commission dug up the bodies and assorted paraphernalia before a crowd of 400 onlookers, according to official sources.

Besides the German items found, they said the fact that the bodies were buried neatly and "with honor" indicated that they were Germans and not massacred Poles. The official sources did not explain why two or three of the bodies were bound together with telephone wire, however.

It all started June 29, when local pensioner Stefan Myszczynski dreamed that he saw the burial site of some of the Poles missing from Giby since the waning days of the war in June 1945. Villagers flocked to the site, six miles from Giby and about the same distance from the Soviet border.

Polish authorities insist that the case is closed, but up to 100 cars with mourners continue to arrive at the site every day. "They want to check the official version," a priest from nearby Sejny said in a telephone interview. "They just don't believe it." An estimated 180 Poles suddenly disappeared from the Giby area at the end of the war in June 1945. Residents have long alleged that Soviet troops killed them, but so far no bodies have been positively identified.