Mentally unstable mother killed two of her daughters in the Daur Tehsil of Nawabshah on Monday night.

Mother is mentallyretarded and locked her three daughters inside a trunk for frustrating her, according to the father.

Nine-month-old Amna and seven-year-old Sania suffocate to death, while the third daughter, a nine-year-old, was shifted to the hospital in a serious condition.

The police said, investigation into the incident is underway.