The Taliban have attacked an Afghan village elder who has been negotiating a ceasefire on behalf of his village with the country's government.
Sayed Badar Agha was beaten after being kidnapped in the town of Sarwan Qala, in Sangin district in Helmand province.
Correspondents say there have been similar deals with Sangin elders before, but all have proved temporary.
Taliban leader Mullah Omar is reported to have ordered the killing of all those involved in such talks.
Sayed Badar Agha led a group of 40 elders from a handful of villages who have been negotiating a truce with the Afghan government.
They met Afghan and international officials, including the Helmand governor.
Nato said in a statement that a peace deal had been brokered with a group of 40 elders in Sangin.
A spokesman for the alliance, Maj Gen Richard Mills, said seven Taliban commanders had put their names to the agreement.
According to local sources, the ceasefire envisages that the Taliban would stop attacks and keep foreign fighters away, and local forces would patrol the area.
In a goodwill gesture to secure the agreement, a local Taliban commander was freed by the Afghan government.
The Taliban then seized the elder who led the negotiations.
Local sources told the BBC's Bilal Sarwary in Kabul that the Taliban was refusing to let the elder leave the village for medical treatment.
The Taliban have not commented to the media.