The blast destroyed several apartments on the upper floors of a five-story building in Naberezhnye Chelny.
A gas explosion in central Russia has partially destroyed a five-story residential building, officials say.
At least six people --including two children -- were pulled alive from the rubble, according to the regional emergencies ministry. More than 30 others were evacuated from the scene.
The blast occurred on Monday evening in the city of Naberezhnye Chelny, 900 kilometres east of Moscow.
The ministry said in a statement that an "air-gas mixture" explosion in a fourth-floor apartment had damaged the building's upper two stories.
"In total, 155 people and 49 pieces of equipment were involved in the elimination of emergencies," authorities said.
"As a result, firefighters and rescuers rescued 4 people from the rubble, including 2 children. Search and rescue work continues."
A temporary accommodation centre has also been set up for those people evacuated from the building.
Gas explosions are relatively common in Russia due to ageing infrastructure and poor safety regulations.
In September, a gas blast at a residential building in Noginsk killed seven people and injured seventeen others.