Police in Pakistan-administered Kashmir say they have arrested a couple on charges of murdering their own daughter in the name of honour.

The couple admitted to killing the unmarried 18-year-old when they found out she was pregnant, police said.

Villagers found the girl's chopped-up body parts in a river, and were able to identify her by the disembodied head.

Such killings were once rare in Kashmir, but police say they are now happening much more frequently.

This is the third reported "honour killing" in the region in five months.

Such killings take place when - usually male - family members believe the victim has brought dishonour to their community.

Human leg

Inspector Mohammad Jameel, the head of Kotli city police station, told the BBC the couple admitted chopping up their daughter's body using an axe.

He said the alleged murder took place in a village near Kotli town on 6 March.

The following day, villagers found a human leg near the bank of the Poonch river and alerted police.

"About five days later we found the head of the girl, which was recognised by the villagers," Insp Jameel said.

In the interim, he said, the girl's parents had moved to the Pakistani city of Rawalpindi, along with their two sons and another daughter.

On 14 March, they reported to the Pakistani police that one of their daughters had gone missing from a busy market in the city.

They have since been detained for questioning.

In October last year in the same Kotli district, police arrested a mother and father on suspicion of murdering their 15-year-old daughter by dousing her with acid in the name of "honour".

The couple later told the BBC, while in police custody, that they had killed their daughter for looking at a boy.

Police say such incidents used to be rare in the Kashmir region but their frequency is now disturbing, reports the BBC's Zulfiqar Ali in Islamabad.

Honour killings are also on the rise across Pakistan, says the country's Human Rights Commission.

In 2011 - the last year for which statistics are available - 943 women were killed, an increase of more than 100 on 2010.