The mammoth An-124 plunged to the ground 20 seconds after takeoff from Irkutsk, damaging four apartment buildings, an orphanage and a school, witnesses said. Scores of terrified children were evacuated.
"I thought somebody was shooting ... I only saw the plane moving quietly to the ground, one wing lower than the other," a woman who saw the crash told the Independent Television channel.
"Everything is in turmoil and things are still not clear," Irkutsk journalist Valery Pochekunin said several hours after the crash. "I can see tens of bodies."
Russian television stations showed pictures of the smashed aircraft's giant tail _ emblazoned with the red star of the former Soviet Union _ leaning against a four-story apartment building. Surrounding buildings were gutted by flames and still smoldering in Irkutsk, 2,600 miles east of Moscow.
There was confusion about the number of people aboard the 220-foot jet, roughly the size of a later-model Boeing 747.
The Defense Ministry said the plane was carrying 46 people, but the Ministry of Emergency Situations, which was heading rescue efforts, put the number at 23. There was no explanation for the contradiction.
Emergency officials said 30 bodies had been found. The death toll was expected to rise as some 700 firefighters, soldiers and medical personnel with heavy machinery and dogs searched for survivors in the debris and in surrounding buildings.
"We don't know how many people are under the debris," said Marina Ryklina of the Ministry of Emergency Situations.
Yevgeny Kozlov, a local emergency service official, said 12 people, including seven children, had been hospitalized in critical condition with burns. But authorities had no overall figures on the number of injured.
The plane had about 100 tons of fuel in its tanks when it crashed and the resulting explosion and fire enveloped the area in flames, local officials said.
The crash occurred at about 2 p.m. local time, when many residents were away doing weekend shopping, averting a much higher death toll, officials said.
The plane's flight recorders were found, but would have to be examined in Moscow for clues on what caused the crash, they said. Skies were clear at the time.
The plane was 10 seconds into its flight after taking off from an aircraft factory airport on the outskirts of Irkutsk when both left engines failed at 210 feet, the ITAR-Tass news agency said. It slammed into the residential neighborhood about 20 seconds after takeoff.
The jet, which belonged to the Russian air force's military transport service, was headed to the far eastern Russian city of Vladivostok.
The plane reportedly was carrying a cargo of two Sukhoi jet fighters from the Irkutsk factory for export to Vietnam, according to the Interfax news agency. The flight was scheduled to fly from Vladivostok to Vietnam.
The four-engine cargo jet, commonly known as the Ruslan, is one of the world's largest aircraft.
President Boris Yeltsin said he was shocked by news of the crash. He ordered Prime Minister Viktor Chernomyrdin to go to Irkutsk and head the investigation into the accident.
"I expect the government ... to carry out a prompt investigation of the causes of the tragedy and find those responsible," Yeltsin said in a statement.
Russia and other nations of the former Soviet Union have been plagued by a series of deadly air crashes in recent years. Experts have blamed poor maintenance, safety violations and cost-cutting for persistent problems, which included a succession of major air crashes in Russia in 1994.
That year there were nine major crashes, including one in which a civilian Tu-154 airliner went down shortly after takeoff from Irkutsk, killing 124 people.
However, Russian aviation officials said recently that aircraft safety was improving following attempts to boost inspection standards.
At least two An-124s have crashed since 1993.