Kandahar: An Afghan man killed his two teenage daughters when they returned home four days after running away with a man in a southern village, police said Sunday.

The father, who shot the girls, has been detained on murder charges in Nad Ali district in the southern province of Helmand, a hotbed of the Taliban insurgency, provincial police spokesman Farid Ahmad Farhang told AFP.

"He killed two of his daughters. His daughters had run away with a young man four days ago. When they returned home their father killed them," Farhang said.

Police have issued an arrest warrant for the young man, who is said to be working as an interpreter with NATO forces in the southern province, Farhang said.

Relations between men and women outside marriage are strictly controlled under Islam and infringements are harshly punished by most families in the troubled Central Asian nation.

So-called "honour killing" is a common practice in Afghanistan, an ultra-conservative Islamic nation which has been at war for most of the past three decades.

The Taliban, an Islamic insurgent group waging war against the Western-backed government of President Hamid Karzai, recently publicly executed a young woman in a village near Kabul after she was accused of adultery.

The execution was widely condemned internationally after a shocking video of the killing surfaced in Afghan media. It showed a crowd cheering as a man shot the woman with a rifle.