Fire broke out in a Moscow nightclub early Sunday, killing 10 people, an Emergency Situations Ministry spokesman said.
The cause of the blaze had not been determined, but some witnesses said it broke out during a "fire show" that was part of the club's nightly entertainment, said Yevgeny Bobylev, a spokesman for the Moscow division of the ministry.
The preliminary accounts indicated that a performer in the show inadvertently set his clothing on fire and that in turn ignited a nearby 5-liter (1.2-gallon) container of inflammable liquid, Bobylev said.
He said all the deaths were due to suffocation. About 150 people were evacuated, including four who were hospitalized.
The club was located on the premises of the Lenkom theater, a well-known stage in downtown Moscow not far from Pushkin Square. Bobylev did not immediately have the name of the club, but police at the roped-off fire scene said it was named "911."
The fire broke out shortly after 3 a.m. (2300 GMT Saturday).
The city prosecutor's office has opened a criminal investigation on suspicion of fire safety violations, the ITAR-Tass news agency reported.
The club blaze draws new attention to Russia's severe problem with fire deaths. Some 17,000 people died in fires last year, according the emergency ministry - a rate several times higher than seen in Western countries. Officials say poor enforcement of fire regulations and improper construction contribute to the high rate, the AP reports.
Last week, a fire killed 63 residents of a nursing home in a southern Russian town, where the local fire department had been disbanded; fire crews took about an hour to get to the scene. A new alarm system had not been fully installed at the nursing home and some reports said a watchman ignored initial alarms from the system, calling for help only when he saw flames.
In December, 45 women died in a fire at a Moscow drug treatment facility where windows were barred; a fire at a Siberian mental hospital the next day killed nine patients.
The choice of the city of Helsinki is not incidental as the capital of Finland had hosted US-Soviet negotiations on the limitation of nuclear stockpiles in 1969