Media playback is unsupported on your device Media caption The rape and murder of six-year-old Zainab sparked outrage in Pakistan

Pakistani authorities say they have arrested the main suspect in the rape and killing of six-year-old Zainab Ansari.

The chief minister of Punjab province accused Imran Ali, 24, of being a serial killer.

Speaking at a news conference in Lahore, Shahbaz Sharif said the suspect had confessed and his DNA matched samples from the crime scene in Kasur.

There has been no immediate comment either from the accused or his lawyers.

Zainab's murder triggered outrage across the country, including riots against alleged police incompetence. Two protesters were killed in the clashes .

The child's body was found in a garbage dump earlier this month, several days after she went missing.

Police in Kasur, which is south of Lahore, say there have been several similar murders in the past two years.

Image copyright CCTV images Image caption CCTV footage showed a man leading away a young girl, believed to be Zainab

In February, a suspect in the killing of another child was shot dead by police when he tried to escape.

Pakistani officials are currently investigating whether that man, named only as Mudasir, was innocent.

Following his death in February, another four young girls were attacked, including Zainab. Three of them died.

Police have been under huge pressure to find who killed Zainab and the other children.

Zainab's family say the police did not take action after they reported her missing and it was relatives who recovered CCTV footage of her last movements.

The footage, which showed a girl being led away by a man, was circulated widely on social media.

Mr Sharif said on Tuesday that they had looked at DNA samples from 1,150 people.

The victim's father, Ameen Ansari, was also at the press conference. He said that after initial reservations, he was satisfied with how the case was proceeding.

According to Geo News, the suspect is known to the family. Mr Ansari has denied rumours that he is a relative.