A top doctor has said that the gas used by elite Russian forces to end Chechen rebels' siege of a Moscow theatre killed 115 hostages.
Survivors of the ordeal - including four with Swiss ties - are recovering in hospital.
The chairman of Moscow's health committee, Andrei Seltsovsky, said on Sunday that 115 hostages had died from "the effects of gas exposure".
Only two of the approximately 800 hostages died of gunshot wounds when special forces stormed the theatre on Saturday morning.
At least 646 of the freed captives are recovering in hospital. One hundred and fifty are in intensive care while 45 are said to be "in a grave condition".
Swiss still in hospital
Five people with Swiss passports or ties to Switzerland were among the hostages.
One man with dual Swiss-German citizenship was flown home on Saturday, Anne Bauty from the Swiss embassy in Moscow told swissinfo.
Another four people remain in hospital, including two Russian employees of the Swiss chemical company Clariant, and a Russian mother and her 10-year-old daughter who live in Villars-sur-Glâne, canton Fribourg.
The young girl was released by her captors on Friday.
"We will not stop until these people leave the hospital and we are sure that everybody is fine," Bauty said.
"Russian authorities have been cooperative, efficient and kind to us," Bauty continued. She said the embassy had not encountered the same problem many victims' families had - namely a lack of information on the whereabouts or safety of the hostages.
The government has so far refused to identify the type of gas used to knock out the hostage-takers, who threatened to blow up the building.
Moscow's head anaesthesiologist, Yevgeny Yevdokimov, reportedly said that the gas used was a "narcotic substance basically similar to a general anaesthetic in surgery."
The crisis began on Wednesday evening when a group of around 50 Chechen separatists took over the theatre, where a popular musical was being staged.
The rebels from the breakaway Caucasian republic were demanding an immediate end to the war in Chechnya and the withdrawal of all Russian troops.
swissinfo with agencies