The leader of a Taleban militia holding a Turkish engineer hostage in south-western Afghanistan have demanded the release of 250 Taleban fighters by the Afghan Government.
Onal was working on a reconstruction project
Abdul Waris Muslim told the BBC his group would settle for nothing less and would hold Hasan Onal for as long as it took.
It came a day after Afghanistan ruled out exchanging Taleban prisoners for Mr Onal.
Meanwhile, the United States has warned that Taleban fighters are planning to abduct American journalists in Afghanistan.
It urged American journalists in the country to take "immediate steps" to increase their personal safety.
In his first interview with the press, Abdul Waris Muslim denied reporters that his group had lowered the number of prisoners they wanted released.
"No such demand was made. We haven't lowered or raised our demand. We don't categorise our men as important or unimportant, and that is the reason we want all 250 of them freed," he said.
Mr Muslim said his group would not harm Mr Onal and said he could make telephone calls to his family or employers.
"We are treating him as a guest. He is in good health," he said.
Mr Onal, who works on a US-funded project to renovate the Kabul-Kandahar highway, was seized along with his driver last week in the province of Zabul.
The driver was released the next day.
On Thursday, Afghan Interior Minister Ali Ahmad Jalali said he would not give in to the militia's demands.
"Afghanistan does not make deals with terrorists. Our work to free the engineer is going on.
"We are hopeful he will be freed and can go home soon," he said.
The US State Department said it had "credible information" that Taleban fighters were planning to kidnap American journalists to bargain for the release of Taleban prisoners "under United States control".
Last week, the United Nations' top peacekeeping official, Jean-Marie Guehenno, said Taleban forces were retaking parts of Afghanistan as the post-war government showed signs of weakening.