President Vladimir Putin said Monday he will give the military broader power to strike against suspected terrorists "where ever they may be" in response to a three-day hostage siege at a Moscow theater that left at least 118 captives dead after a rescue operation.

All but two of the hostages who died after Russian special forces raided the theater succumbed to a mysterious knockout gas troops pumped into the auditorium before storming it, doctors said. However, the substance remained secret even as doctors treated the hundreds of survivors.

"If anyone even tries to use such means in relation to our country, Russia will answer with measures adequate to the threat to the Russian Federation — in all places where the terrorists, the organizers of these crimes, or their ideological or financial sponsors are located. I emphasize, where ever they may be," Putin said in a televised statement.

Putin told Cabinet officials he would order the Russian general staff to change its guidelines on the use of military forces because of the growing threat of international terrorism and the possibility of them using weapons that could cause as much damage as weapons of mass destruction.

"Russia will not ... give in to any blackmail," Interfax quoted Putin as saying.

Putin has sought to portray the Chechen conflict as a battle with international terrorists, partly in efforts to get broader support abroad.

Putin's announcement came as the government came under increasing criticism about the number of hostages killed at the theater and the way they died: at the hands of Russian authorities trying to save them.

Three top Moscow doctors revealed Sunday that the gas killed the people inside the theater and they were unclear about how to treat the estimated 750 people inside.

Authorities did not tell medical officials what type of gas they pumped into the theater shortly before special forces troops raided it early Saturday, chief Moscow doctor Andrei Seltsovsky said.

Seltsovsky said doctors were familiar with the general category of the gas, which causes people to lose consciousness and can be used to anesthetize surgical patients, but were not told its name.

The gas can paralyze breathing, blood circulation, and cardiac and liver functions, doctors said. The effects were worsened by the extreme conditions in which the hostages were confined for three days — little movement, lack of water, food and sleep, severe psychological stress — and by the chronic medical problems some suffered.

"In standard situations, the compound that was used on people does not act as aggressively as it turned out to do," Seltsovsky said.

The Moscow Health Department said 405 former hostages, including nine children, remained hospitalized Monday after 239 were released. On Sunday, doctors had said 646 people remained hospitalized, 45 of them in very serious condition.

Two foreign women, one Dutch and one Austrian, died, and officials in Kazakhstan said a 13-year-old girl from their country died — one of three children who perished.

There were about 800 people in the theater when it was seized by Chechen gunmen during Wednesday night's performance of the popular Russian musical Nord-Ost, or "North-East."

Anguished relatives crowded the gates of Moscow hospitals, begging for news of their kin, while others scoured the city morgues.

Tatiana Lukashova's 26-year-old daughter, Masha Panova, was a hostage and now is missing.

Lukashova saw a broadcast on the ORT television station Saturday that showed her daughter lying on a mattress in a hospital corridor with an oxygen mask on.

"But we didn't hear what hospital it was, and our search through all the hospitals was in vain," Lukashova said in a telephone interview.

"It's unbelievable," she said, tears choking her voice. "Even the head of the district where we live went to meet officials of ORT to find out in which hospital they filmed the girl, but they told him they can't tell without permission from prosecutors."

Even diplomats had trouble finding information about the estimated 70 foreign citizens among the hostages. U.S. consular officials searched the city's hospitals for one of two American citizens known to have been hostages.

Putin declared Monday a day of national mourning for the victims of the hostage crisis. Schools in Moscow were open Monday and started the day with a moment of silence, but many children's activities were canceled.

The death toll among the hostages stood at 118 on Sunday, including the 116 who died from effects of the gas, a woman who was shot in the early hours of the crisis and a hostage killed by a gunshot wound to the head early Saturday.

Moscow officials said Monday that relatives of the dead would receive about $3,150 in compensation, while hostages who survived would get half that, Interfax reported. The city will pay for funerals, it said.

Officials said three gunmen were captured, and authorities searched the city for accomplices who may have escaped. The Federal Security Service said 50 assailants were killed at the theater, and several were shot in the head apparently as they lay incapacitated from the gas.

Meanwhile, security remained tight in the capital and police arrested a Chechnya resident in downtown Moscow after finding an explosive substance on him and in his car, the ITAR-Tass news agency reported Monday. The man also had extremist Muslim literature, it said.

Some of the attackers who burst into the theater Wednesday night had explosives strapped to their bodies; 18 were women who said they were widows of Chechens killed by Russian forces.

They mined the theater and threatened to blow it up unless Putin withdrew Russian troops from the rebellious, predominantly Muslim region of Chechnya.

Russian forces pulled out of Chechnya after a devastating 1994-1996 war that left separatists in control. In the autumn of 1999, Putin sent troops back in after Chechnya-based rebels attacked a neighboring region and after apartment bombings that killed about 300 people were blamed on the militants.

In 1995 and 1996, rebels seized hundreds of hostages in two raids in southern Russia near Chechnya, and dozens of people died in both cases. Many of them were killed when Russian forces attacked the assailants.