One of the injured persons is critical, police said.
There was leakage in the LPG cylinder at a house in Ambedkarnagar area of the old city and unaware of it, a woman turned on the gas stove leading to an explosion and spread of the blaze, Kothapet police station inspector Subba Rao said.
The house's roof collapsed under impact of the impact, he said.
Three women - Ramanamma (80), Nirmalamma (48) and Ramana (56) - died on the spot, he said.
According to doctors, one of the injured was critical, he said.
A case has been registered in this regard, Rao added.
