Updated

A natural gas blast ripped through an apartment building in Russia's Tatarstan region early Wednesday, killing at least seven people, officials said.

Others were feared trapped beneath the rubble in freezing temperatures.

The explosion brought down an entire section of the three-story brick building in Tatarstan's capital, Kazan. Russian television showed a jagged remnant of a wall and a pile of rubble with smoke or steam wafting into the frigid air.

Six bodies were found in the rubble, and a woman who was hospitalized later died, said Olga Trofimova, spokeswoman for the Emergency Situations Ministry in the Volga River area. She said two people remained hospitalized.

Officials said a handful of people could still be trapped in the rubble.

The explosion, which sparked a fire, was apparently caused by a gas leak, said Viktor Beltsov, spokesman for the Emergency Situations Ministry in Moscow.

A distraught woman told First Channel television that a 7-year-old girl and her grandfather, apparently relatives, were missing.

"We found grandmother, she's in the emergency room," the woman said. "We don't know where grandfather is, and we don't know where (the girl) is. She's nowhere to be found."

Rescue efforts were complicated by the cold and fires smoldering beneath the rubble, an unidentified emergency worker said in televised comments. The temperature in the city, 450 miles east of Moscow, was forecast to drop as low as minus 18 on Wednesday night.

The blast destroyed or damaged 12 apartments, emergency official Ferdinand Timurkhanov said on First Channel television.

Neglect of safety precautions and poor infrastructure has led to frequent gas explosions in Russian apartment buildings and public facilities.