TASHKENT, U.S.S.R. -- Last April, Khasnutdin Makhmudov returned home early from his obligatory two-year service in the Soviet army -- in a coffin. The official explanation for his death was that he had accidentally fallen into a concrete mixer while fulfilling his duty to the socialist motherland.

Overriding strenuous army objections, Makhmudov's parents insisted on an independent autopsy, which revealed the presence of three long knife wounds near the heart. Doctors concluded that he had been stabbed in a fight and then thrown into the mixer as a way of covering up the murder.

In one sense, there was nothing out of the ordinary about Makhmudov's death. This year alone, nearly 400 young Uzbeks have died while performing their military service. The number of Uzbek soldiers dying in peacetime is now roughly three times the casualty rate for Uzbeks during the brutal 10-year war in Afghanistan.

What made the murder of the young conscript unusual was the reaction it provoked in Uzbekistan, traditionally regarded as one of the most conservative republics in the Soviet Union. Tens of thousands of Uzbeks joined in the funeral procession in Tashkent, breaking through police lines to carry the coffin to the headquarters of the Uzbekistan Communist Party.

Allegations of indiscipline and hazing in the armed forces have provoked a surge in anti-military sentiment across the Soviet Union, from Lithuania to Siberia. Yesterday, President Mikhail Gorbachev received dozens of parents of soldiers killed in peacetime who had camped out overnight in a Kremlin reception room to demand sweeping military reforms.

"I share your grief and it is difficult for me to talk. Nothing can compensate you for your losses," said Gorbachev, who promised to set up a presidential commission to investigate the growing number of servicemen's deaths.

The peacetime deaths of soldiers have become a particularly sensitive issue in Uzbekistan and the other Central Asian republics because of the extremely high number of recruits that they are now obliged to contribute to the Soviet armed forces. One-third of all Soviet conscripts come from Central Asia, whose predominantly Moslem population has a birthrate several times higher than that of ethnic Slavs.

"Our kids are being exploited. Many of them are drafted into construction battalions, which amounts to a kind of forced labor. At the same time, there are very few Uzbek officers. The Soviet Union names some 500 generals a year, but there are only five Uzbek generals in the whole Soviet army," said Karim Bakhtiar, an Uzbek journalist and independent member of the Uzbekistan assembly.

At about the same time that Makhmudov was thrown into the concrete mixer, dozens of Uzbek conscripts died in almost equally gruesome ways, according to official army records obtained by Bakhtiar. Flirom Navryzov "fell" under a train. Tohirzhon Isakov was poisoned by gas. Abducadih Medaliev died from stab wounds in the head. Aligher Alimov's skull was cracked open. Murlibeh Smanov and Murzhon Dzhasanbekov hanged themselves.

The army maintains that the casualty rate among Uzbek conscripts is not significantly higher than in civilian life and that many soldiers die accidentally or of natural causes. This claim is contested by opposition groups. While acknowledging that a third of the deaths are due to "illness," they maintain that many Uzbek conscripts are physically unfit for military service.

"Our soldiers are generally weaker than the average Russian or Ukrainian. Health conditions are worse here and there is a widespread tradition of child labor. The army approaches the draft as if they were fulfilling a plan," complained Bakhtiar.

Faced by the unprecedented public outcry, Uzbek President Islam Karimov has promised to try to persuade the army to group the Uzbek conscripts in ethnically homogeneous units where they will be protected from attacks by other nationalities. A recent presidential decree forbade the armed forces from sending Uzbeks to serve in construction battalions outside Central Asia.