be killed and set alight as punishment for helping her friend to marry of her own free will.

The girl was kidnapped, drugged and killed and then placed in the back seat of a parked van that was doused with petrol and set on fire, Dawn reported.

Other media reports said the victim was still alive when the van was set alight.

'Honour killings'

A local official who brought the charred body to the morgue said: "We went to the place and found three vehicles parked next to each other that were burnt. In one of them we saw a body. We couldn't recognise her then. But found a few bangles on one of her arms establishing that this was a woman's body."

Thirteen people have been arrested, police said.

The girl's school friendand her boyfriend are reported to have married and be living at an undisclosed location.

Correspondents say so-called honour killings are a major issue in Pakistan and many go unreported.

Last year, nearly 1,100 women were killed by relatives who believed they had dishonoured their families, a report by the country's independent Human Rights Commission said.

In February, Punjab, the country's largest province, passed a landmark law criminalising all forms of violence against women.