A six-year-old girl has allegedly been raped by her step-father in Pakistan's Sindh province - Representational image Getty

Pakistani police have arrested a man for allegedly raping his six-year-old stepdaughter in Karachi in Sindh province. The victim has reportedly suffered serious injuries during the sexual assault and is undergoing treatment at a local hospital. She also underwent a surgery.

Many brutal cases of rape are being brought into the spotlight in Pakistan since news of Zainab Ansari's murder sent shockwaves across the country. The girl's body was found in a heap of trash in the city of Kasur on 9 January, five days after she had gone missing.

In the latest sexual attack which took place on Sunday (18 February), authorities said they have taken the suspect into custody after receiving a complaint from the victim's mother. The mother married the suspect, who has not been named, about two years ago after separating from her first husband. Medical treatment is being conducted to confirm the rape.

According to the complaint reported by Dawn newspaper, the assailant had locked his stepdaughter in his house when the victim's mother was not present there and then raped the child. She was found bleeding profusely when her mother returned.

The suspect has denied any wrongdoing and the police have promised to conduct a thorough investigation.

Meanwhile, a special anti-terrorism court in Lahore convicted the perpetrator, Mohammad Imran Ali, in Zainab's case. Ali, suspected to be a serial killer, has been sentenced to death on four counts.

A medical examination later found the victim was raped before being strangled to death. The exact age of Zainab is still unclear, with reports suggesting she was six to eight years old.

Following the incident, a top Senate body in Pakistan had recommended that convicts who have raped minors be hanged in public as a sign of harsh punishment to deter others from committing such heinous crimes.