As many as 90 hostages died early Saturday morning when Russian special forces stormed the Moscow theatre where Chechen rebels had been holding hundreds of people captive.

With sleeping gas wafting through the theatre in hopes of knocking the gunmen out, commandos were ordered to storm the building, Russian officials said, after gunfire was heard inside.

Military spokesman Sergei Ignatchenko said the rebels had started to execute the hostages.

Late Saturday, Russian media reported the health ministry put the number of hostages killed at 90.

Deputy Interior Minister Vladimir Vasilyev had earlier said 67 hostages were dead, but couldn't say how many were executed by their captors and how many had been caught in the crossfire during the raid.

Vasilyev said 750 captives had been released. He added that no children were among those killed, nor were any of the 71 foreigners.

The rebels had said they would start killing the more than 700 hostages at dawn Saturday if Russia hadn't declared an end to the war in Chechnya.

Most of the rebels killed

The raid left 50 rebels dead, including their leader, Movsar Barayev.

Russian television crews were allowed into the building shortly after the raid, where they filmed the black-clad bodies of dead rebels, many of them still wearing undetonated explosives around their waists.

Armed with machine-guns, dozens of rebels had stormed the theatre on Wednesday evening during a performance of a popular musical. They took everyone inside hostage and told authorities they had mined the building.

The Chechens talked about being on a suicide mission, creating fears the incident would end in a bloody massacre or with the rebels blowing up the building.

Russian authorities had said they wouldn't give in to blackmail.

Following the raid, hundreds of hostages were whisked away in buses. Many of them appeared to be in shock, or even unconscious, possibly from the gas.

Captured rebels were brought from the theatre with their hands bound. Some apparently escaped, and police were searching for them.

Friday night was tense before the raid, with explosions and gunfire heard periodically.

Earlier Friday, the rebels freed eight children unharmed. As many as 30 children remained inside.

Hopes were raised that the hostage-taking would end peacefully when the Red Cross announced that 75 foreigners were being freed.

But the deal collapsed Friday afternoon, and the rebels issued an ultimatum for Russia to begin pulling troops from Chechnya by 6 a.m. Saturday.

A woman with dual British and Canadian citizenship was believed to be among the captives. Other foreigners included Americans, Britons, Australians, Germans, Dutch and Austrians.

Toronto man in hospital

A Bulgarian man from Toronto also survived. Vesselin Nedkov, 28, is recovering in a Moscow hospital.

Nicolas Nedkov told CBC Newsworld he spoke to his brother and learned he is in good condition, although feeling exhausted after three days with no food or water.

Nedkov said his brother confirmed reports that some of the hostages tried to fight their captors after the rebels said no one would get out alive.

"We lived through a terrible two hours. We knew that the (special forces) operation was over. But we didn't know anything about him," Nedknov said of his brother. "He could have been one of those who died."

Just over 50 hostages were released since the Chechens attacked. A couple of people managed to escape Thursday.

Before Saturday morning, it was believed only one hostage had been killed a woman shot when the siege began. Her body was removed by medics 24 hours later.