In the latest case of honour killing in Pakistan, a teenage boy on Thursday stabbed his younger sister and let her bleed to death.

Hayat Khan attacked his 17-year-old sister Sumaira with a knife multiple times after he found her talking to a man on her mobile phone at their home in the Orangi Town, senior police officer Azfar Mahesar was quoted as saying by The Express Tribune.

The girl succumbed to her injuries during medical treatment at the Abbasi Shaheed Hospital.

Investigating officer Gulzar Ahmed confirmed the details of the attack adding the girl had suffered multiple stab wounds to the neck, chest and back.

The suspect, who was taken into custody by local police, said he saw his sister talking to someone on the phone at their doorstep, the police official said.

"The victim refused to say anything which made her brother suspicious and he attacked her with a kitchen knife," the official said.

Women in Pakistan have fought for their rights for decades, in a country where honour killings and acid attacks remain commonplace.

More than 500 men and women died in honour killings last year, according to the Human Rights Commission of Pakistan.

Many of these crimes, carried out by relatives who say their mostly female victims have brought shame on the family, are never prosecuted, observers say.

Last month, a young couple from North Waziristan Agency had been shot dead for marrying of their free will. They were killed allegedly by the woman's uncle and his son inside their house in Orangi Town.

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