PESHAWAR (AFP) - Relatives have shot dead three women in a lawless tribal area of north-west Pakistan after one of them left her husband, officials said on Monday.

The "honour" killings happened in Jawaki village in the Darra Adam Khel district, between the cities of Peshawar and Kohat.

A 22-year-old woman from Karachi who married a Jawaki shopkeeper about two years ago was accused of fleeing her husband's house and marrying another man in the northwestern Swat valley with the help of her aunt and cousin, a local administration official told AFP.

The local tribal council or jirga intervened in the matter and decided on Sunday that the women should be killed.

Relatives shot the three dead at their house late Sunday and buried them on Monday morning, he added.

"It is a case of honour killings and was settled under tribal customs where the Pakistani criminal code is not applicable," the official told AFP on condition of anonymity.

"According to the information gathered from local sources, the girl was not happy with her husband."

Local intelligence officials confirmed the killings.

The Human Rights Commission of Pakistan says 943 women and girls were murdered in 2011 after being accused of tarnishing their families' honour.

The statistics highlight the violence suffered by many women in conservative Muslim Pakistan, where they are frequently treated as second-class citizens.