The Taliban is demanding the body of an assassin who shot dead a powerful Afghan police chief, in return for the remains of 13 people killed in an army helicopter crash in territory controlled by the militants.

Tribal elders in the restive western province of Farah bordering Iran have been handling negotiations for the exchange of bodies for nearly a week.

So far only 12 of the 25 people killed in the helicopter accident in Taliban-controlled Anar Dara district on October 31 have been given to Afghan authorities.

Officials blamed bad weather for the crash, but the Taliban claimed its fighters brought down the aircraft.

“We want to hand over the bodies from the helicopter crash to their respective families via the International Committee for the Red Cross, but on condition that the enemy hand over the body of martyred fighter Zabihullah Abu Dajana, who killed Commander Abdul Raziq, to his family,” Taliban spokesman Qari Yousuf Ahmadi said in WhatsApp message.

Among the bodies returned were those of provincial councillor Jamila Amini, civilians and businessmen, Farah governor spokesman Nasir Mehri told AFP.

“No military officials have been recovered yet,” Mehri said.

Farah police spokesman Mohibullah Mohib confirmed that 12 bodies had been recovered thanks to the efforts of tribal elders.

“The rest of them are still with the enemy,” he added.

The bodies still in Taliban hands include those of the deputy army corps commander for western Afghanistan and the head of the Farah provincial council.

Such horse-trading of bodies between the Taliban and tribal elders acting on behalf of the Afghan government is not unusual.

But the remains of the gunman who killed General Abdul Raziq, a renowned anti-Taliban strongman credited with keeping a lid on the insurgency in the south, has particularly high propaganda value for the militant group.

Raziq was among three people killed when the shooter wearing an Afghan security forces uniform opened fire on a high-level security meeting in Kandahar city on October 18.

General Scott Miller, the top US and NATO commander in Afghanistan, was standing near Raziq and narrowly escaped unhurt.

Since the attack, the killer's body has been kept in the morgue of Mirawais hospital in the provincial capital, a Kandahar health official told AFP on the condition of anonymity.

Muslims typically bury the dead as quickly as possible, normally within 24 hours of a person's death.