A district court here ruled today that Japan conducted germ warfare in World War II, bluntly contradicting the continued insistence by the government that there is no proof of such crimes. But the court rejected claims for compensation by elderly Chinese victims.

The compensation ruling was a blow to the Chinese who traveled here during the trial to describe the horrible deaths of loved ones killed by rare diseases during the fighting with Japanese forces in 1941 and 1942.

"This is so unjust," said Chen Zhi Fa, 69, who came from Zhejiang province to testify about the deaths of his father and brother in 1941. "This cannot prevail."

Despite testimony from former Japanese soldiers involved in the biological experiments, the Japanese government contends there is no proof that the Imperial Army spread fleas infected with bubonic plague over the Chinese countryside and infected food with cholera during its wartime invasion of China.

While brushing aside that denial, the court ruled that wartime victims could not collect compensation from the Japanese government.

The decision follows a pattern in which Japanese courts have -- with rare exceptions -- rejected a string of legal claims slowly emerging from the shadows of Japan's Asian conquests during World War II. Lawsuits brought on behalf of slave laborers, women forced into prostitution for Japanese troops, torture victims, Koreans forced into military duty and Allied prisoners of war have all been dismissed.

The suit over germ warfare was brought after historians had painstakingly peeled the secrecy back from the activities of Japan's notorious Unit 731, which carried out the biological experimentation in China. Former members of the unit, who said they were wracked by guilt, testified to horrific experiments on Chinese. Japanese lawyers who volunteered to help bring the case presented eyewitness accounts of 180 Chinese residents, and some elderly Chinese boldly made the trip here to testify.

"Japan has a serious problem. The legal system needs overhaul," said Wang Xuan, 50, whose search into her family's past led her to help organize the case. "It is absurd that the ruling confirmed Japan's biological warfare, but the Japanese government doesn't have to take any responsibility."

Victims in the case said they felt they had been denied justice at every turn. Some members of Unit 731 became pillars in the Japanese medical and business communities after the war and were never prosecuted; in fact, they held regular reunions.

The United States made a secret deal to exempt the biological war crimes from the Tokyo trials held after the war, in exchange for the results of the gruesome experiments. The Japanese government denied the existence of the deal and the secret unit for years, and still insists in the face of journals, documents and testimony that it doesn't know what the unit did. Nationalist historians have gained increasing acceptance for accounts that diminish or omit the army's use of biological and chemical weapons against the Chinese.

In its ruling today, read by Presiding Judge Koji Iwata, the court said, "The evidence shows that the Japanese troops, including Unit 731, used bacteriological weapons under the order of the Imperial Japanese Army's headquarters and that many local residents died."

But the court rejected the lawsuit's request for damages of $84,000 to each person because "no international law that enables individuals to sue for war damages had been established at the time or has been now."

Keiichiro Ichinose, a Japanese attorney for the Chinese, said the loss was tempered by the unqualified declaration about the biological warfare.

"The fact that the court confirmed it is revolutionary," he said. "But the court did not have the courage to admit responsibilities on the part of the Japanese government. I think there will be a time when [the government] will have to admit it. In that sense, this is the first step."

Neither the government's attorneys nor Foreign Ministry spokesmen would comment after the ruling. The trial, which has played out over nearly five years, has drawn only perfunctory media coverage in Japan. Many Japanese say they are tired of the arguments about a war that has been over for more than half a century. But China, North Korea and South Korea say the issue remains relevant, contending that Japan has failed to confront its wartime crimes like Germany did.

Although the Soviet Union tried 12 Unit 731 members in 1949, their gruesome accounts at the trial were dismissed by the United States as Cold War propaganda. In 1981, an American journalist revealed the agreement between the United States and Japan not to prosecute Unit 731 members. The following year, author Seiichi Morimura exposed the unit's history to Japanese in "The Devil's Gluttony."

Testimony at the trial bolstered what historians found in documents pried from archives or discovered by accident, and in the accounts of several Unit 731 members given during an extraordinary public confession in 1993. That evidence confirmed the Imperial Japanese Army had mounted an ambitious program to try to spread plague and disease behind Chinese lines during the war.

Japanese researchers grew fleas in a bathtub, mixed them with wheat to attract disease-carrying rats, infected them with bubonic plague, and airdropped them over China's eastern province of Zhejiang and central Hunan province from 1940 to 1942, according to witnesses at the trial.

The Chinese plaintiffs described the unseen and unknown disease that raced through towns and villages. People died in hours or days, their bodies swollen and black. Those who came to their funerals often took the disease home with them, said Ding De Wang, 69, who testified that his father died in convulsions two days after being exposed to the plague. At the time, Ding was 8.

The Chinese government estimates diseases introduced by Japan killed 270,000 civilians, though there is little evidence to support the figure. Yoshio Shinozuka, 77, a member of Unit 731 who volunteered to testify, told of the human experimentation that went on at the unit's Harbin headquarters in northeastern China. Subjects were injected with the plague, and split open moments after, or perhaps even before, they died in agony so researchers could perform an autopsy, Shinozuka testified. He said they were referred to as "logs, like pieces of wood."

China claims about 3,000 subjects died in experiments to produce such diseases as cholera, plague and anthrax as weapons of war. Some have compared the experimentation to that of Nazi doctor Joseph Mengele.

The Japanese government's stance on reparations for its wartime conduct is that they were settled by the 1951 San Francisco Peace Treaty that formally ended the Pacific War, and in subsequent bilateral treaties.

Special correspondent Akiko Yamamoto contributed to this report.

Chinese plaintiffs hold portraits of war victims as they enter Tokyo District Court, which ruled that Japanese troops dropped fleas infected with bubonic plague on China in the early 1940s.Chinese plaintiffs and Japanese supporters stage a rally in Tokyo after the court rejected the plaintiffs' compensation claims.