Migrant labourer Kamal Nath, his wife Seema and their children were asleep in the Chitti Colony slum area when their 'jhuggi' was engulfed by flames this morning, they said.
Sonu (5) and his younger sister Kamana (14 months) died of burn injuries on the spot while their sisters Payal (7) and Sonia (3) were rushed to Rajindra Hospital at Patiala with critical burn injuries, SHO Ladhowal, P S Gurmit Singh said.
Police said that the slum did not have an electricity connection and fire apparently started from a candle that was used for lighting the 'jhuggi'.
Further investigations were under progress, Singh added.