Gurgaon, Sep 10 (IANS): In a tragic incident, two infant sisters -- four and two years old -- suffocated to death after they accidentally locked themselves in their father's car while playing hide-and-seek and could not open it later.

The girls -- Himanshi, 4, and her sister Pinki, 2 -- were playing hide-and-seek outside their house in Kadarpur village of Gurgaon on Wednesday.

They locked themselves in their father Satbir Singh's car by pressing the button of the central locking system, police said on Thursday.

Himanshi had just returned from school on Wednesday afternoon, and after having her meal, she picked up the keys of the car parked outside the house.

One of the sisters pressed the locking system button while playing inside but did not knew how to open it.

All the family members were at home but they thought the children might have gone to their uncle's house in the neighbourhood.

The family went out to search for the children around 4.30 p.m. for sending Himanshi to her private tution classes.

The girls' father found them unconscious on the rear seat of his car, when he was about to go to a police station to report about his missing daughters.

The girls were rushed to a hospital where they were declared dead. The bodies were handed over to the family after a post-mortem examination.