LAHORE/ISLAMABAD, PAKISTAN (REUTERS) - Comments by the lead police investigator suggesting that the victim of a gang-rape in Pakistan that occurred along one of the country's most secure highways was to blame have spurred cries of outrage.

Investigators say the victim left her home with her two children in Lahore and was driving when her car ran out of fuel at around 1.30am.

She called a relative and a helpline for the highway police, but before they arrived, two men approached, broke the car's windows, and dragged the woman and her children to a field beside the highway, where she was gang-raped.

Twelve suspects had been arrested so far, Musarrat Cheema, a spokesman for the government of Punjab province, said on Twitter.

Prime Minister Imran Khan said in a statement on Twitter he was following the case closely and had asked investigators for the "arrest and sentencing of those involved in the incident as soon as possible," adding that his government would look into how to strengthen laws to deal with an apparent increase in cases involving the rape of women and children.

On Thursday, Omar Sheikh, the lead investigator in the case, said in a TV news programme that the victim should have taken another highway, the Grand Trunk (GT) Road, and should have made sure she had enough fuel for the journey.

The highway the attack took place on was constructed to replace the centuries-old and traffic-plagued GT Road, and is equipped with CCTV and a dedicated police force.

Sheikh declined to comment when contacted by Reuters.

Shireen Mazari, the minister for human rights, said on Twitter that the investigator's remarks were "unacceptable."

"The right to access public spaces and safe mobility is a fundamental right of every person in Pakistan, including women," the Women in Law Initiative, a group of women lawyers and rights advocates, said, in a statement condemning the attack and pointing out an increasing frequency in similar cases of violence against women and girls.

In February, lawmakers passed a Bill calling for those convicted of the sexual abuse and murder of children to be hanged in public.

But the government opposed the Bill and it was not enacted into law.