Story highlights

At least four people are feared trapped

Emergency crews use ropes, shovels and cranes

NEW DELHI, India CNN  — 

A three-story building caved in Wednesday in southern India after a cooking-gas canister exploded, authorities said.

At least four people were feared trapped under the rubble of the collapsed structure in Bangalore, city police spokesman V. Ramaiah said.

The explosion occurred about 2 p.m. local time, according to police.

Ramaiah said the building was a residential complex, although some news reports suggested it was a wedding hall. TV footage showed it crashing down and engulfed by a fireball.

Emergency crews used ropes, shovels and cranes to remove huge slabs of concrete.

At least one person was hauled out of the debris in a stretcher.