Emergencies minister Yevgeny Zinichev told Putin that between 36 and 40 people could be trapped under the rubble.
Rescue services in the Russian city of Magnitogorsk scrambled to find survivors after a suspected gas blast in the early hours of Monday caused the partial collapse of a high rise apartment building, killing at least two people, news agencies reported.
The blast rocked the apartment complex at around 4 a.m. local time, completely collapsing one of its sections.
Authorities said five people were hospitalized with injuries, and 35 other residents remained unaccounted for in the accident in Magnitogorsk, a city of 400,000 about 1,400 kilometres southeast of Moscow.
Officials said the blast ripped through the building at around 0600am local time when many residents were asleep.
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News agency TASS said 79 people were unaccounted for, quoting Chelyabinsk regional Deputy Governor Oleg Klimov.
National television showed rescue workers combing through mangled heaps of concrete and metal in temperatures of minus 18 Celsius (minus 0.4 Fahrenheit). Cabinet officials arrived in Magnitogorsk to oversee the rescue efforts. The residents have been evacuated.
The high-rise was built in 1973 and was home to around 1,100 people.
Dubrovsky said later that some apartments were leased and in general, 120 people, were housed in the collapsed part of the building.
There have been several similar incidents in Russian Federation in recent years due to aging infrastructure and poor safety regulations surrounding gas usage.