The US military in Afghanistan says they have no information about a claim by the Taleban that they have executed an American special forces soldier.
Hundreds of soldiers have been searching for the missing soldier
A Taleban spokesman said that the group, which claimed to have held the serviceman, had killed him and dumped his body in eastern Konar province.
The US military says there is no evidence to support the claim and they were trying to locate the soldier.
The soldier was part of an elite unit that went missing on 28 June.
Two members of the team were later found dead while a third was rescued.
Abdul Latif Hakimi, a man who says he speaks for the Taleban, told some news organisations that the missing soldier had been beheaded in the Shegal district of Kunar province, where the four-man special forces team went missing.
"We don't have anything on that claim. We are continuing to search for the service member who has been missing since 28 June," US spokeswoman, Lieutenant Cindy Moore said.
The governor of Konar province, Asadullah Wafa, told the BBC his officials are checking the Taleban claim.
The Taleban say they have been holding the soldier for more than a week, but they have not provided any video footage they said they had filmed of the man, nor of the moment they say they shot down a US helicopter in the same area.
Reports say hundreds of US soldiers and Afghan forces have been scouring the mountains in the province to locate the missing soldier.
A US Chinook helicopter which was sent to back up a ground unit was shot down, with all 16 soldiers on board killed. The Taleban say they brought it down.
It was the heaviest number of deaths US forces have suffered in a single incident in Afghanistan since toppling the Taleban in 2001.
The downing of the US helicopter was followed by an American bombing raid in Konar province which left 17 civilians, including women and children, dead.
Recent months have seen an sharp rise in activity by the Taleban and their allies in south-eastern and eastern Afghanistan.
They have vowed to disrupt parliamentary elections due to be held in September.