Doctors said that only two hostages had died from gunshot wounds before Russian special forces stormed the theater and killed 50 militants, ending a 58-hour standoff. The rest of the civilians who were killed had been weakened by the long ordeal and died "from the effects of the gas exposure," said Andrei Seltsovsky, head of the Moscow health department. Of the 646 former hostages who remained hospitalized today, 45 were in critical condition.

The medical findings, and new accounts from those who were trapped inside the theater, indicated that the Chechen militants had not begun systematically killing their hostages as Russian authorities believed before launching the assault. Some specialists said security agencies used an excessive dosage of the gas, which was funneled into the ventilation system of the theater building. The government's refusal to identify the gas, even to doctors treating the freed hostages, and its decision to keep most of the hostages incommunicado in hospitals provoked new controversy today.

Although the Chechens had threatened to kill hostages starting at dawn, they also had kept lines of communications open to the end. A Chechen intermediary said in an interview Saturday that militant leader Movsar Barayev was negotiating the release of foreign hostages even as the raid began.