MOSCOW, October 27 (IslamOnline & News agencies) - The United States asked the Russian authorities to reveal what gas was used by special forces in their assault to rescue hostages from a Moscow theatre but has not received any reply, a U.S. Embassy spokesman said Sunday, October 27.

"We asked the Russian authorities about the type of gas used but we have not been informed. We're still waiting for a response," the spokesman, who asked not to be named, told Agence France-Presse (AFP).

"We have a hostage in the hospital and it's relevant to her treatment," the official said, adding that U.S. consular officials were talking to her doctors and U.S. physicians were on the way to the hospital.

The authorities have refused to say what gas they pumped into the theatre where some 800 people were held by Chechen rebels for three days, prompting doctors to complain that they do not know how best to treat the patients.

Hundreds of hostages who survived the ordeal are ill in hospital, many in serious condition from what is believed to be the after-effects of the gas, used to incapacitate the hostage-takers before the assault.

According to doctors quoted by the Kommersant daily, it was either sleeping gas or a nerve gas.

One hundred and eighteen hostages have been confirmed dead after the Russian assault.

The spokesman said U.S. authorities had located one American so far, but they were still searching for two other U.S. nationals believed to have been in the theatre.

Meanwhile, doctors involved in treating survivors said Sunday that a Dutch national and a Kazakh teenager, who died after Russian special forces launched the assault to rescue the hostages, succumbed to gas poisoning.

The unnamed doctors were quoted in a report on the privately-owned NTV television.

A diplomat at the Dutch Embassy in Moscow confirmed that one of its nationals of Russian origin, Natalja Zjirov, 38, had died in hospital late Saturday, the Interfax news agency reported.

She is the only Western casualty so far among the 75 foreigners who were held hostage.

A 13-year-old Kazakh girl, Alexandra Litiaga, also died in hospital, local media quoting the Kazakhstan Foreign Ministry said.

A third non-Russian, Belarussian national Lyudmila Bogacheva, 55, also died, the RIA news agency said.

The three had been among more than 800 people taken hostage in the theatre last Wednesday by heavily-armed Chechen rebels demanding an end to Russia's war in their southern breakaway republic.

Witnesses said many of the hostages were overcome by an incapacitating gas pumped into the theatre by Russian special forces immediately before the Saturday pre-dawn assault.

Russian authorities said Saturday that more than 750 people had been rescued, but since then the number of dead has edged up to 118 and the final toll is still not known.

Nearly 350 of the rescued hostages were taken to hospital, according to the authorities.

An Internet news service, gazeta.ru, reported that at least 546 of the freed hostages had been hospitalized, many in serious condition from the gas.

An AFP employee, who was among the hostages rescued from Chechen rebels, said Sunday that a mystery gas used by Russian forces in the raid was pumped in through the ceiling and left him feeling "as if I had drunk a ton of vodka."

"I was less intoxicated than the others. I had a bandana around my neck and I pressed it against my face," said AFP editorial assistant Oleg Zyogonov, 26, speaking by telephone from hospital.

"I passed out and then regained consciousness, this happened several times. It was as if I had drunk a ton of vodka. I heard shouts and lots of gunshots, as in a fight," he added.

It was then that Zyogonov spotted "a light mist coming down from the ceiling. Then, nobody saw anything."

"We all laid down when we smelt gas," Zyogonov said. "Everyone understood the assault was in the offing."

While coming out of the theatre, Zyogonov saw many bodies lying on the floor, but none of them bore bullet impacts - an account that seemed to confirm reports that the mystery gas caused some of the hostage deaths.

"I saw no bullet impact on the bodies," he said.