The United States has not taken a decision on whether to release five prisoners being held at Guantanamo Bay to support a nascent peace process with the Taliban, the US special envoy to Afghanistan and Pakistan said on Sunday.
Marc Grossman, after two days of talks in Kabul with Afghan President Hamid Karzai and advisors, said he agreed with Afghan government demands that any negotiations should be under the umbrella of "a peace process among Afghans".
He also said any release of Taliban prisoners would first have to be agreed by US lawmakers.
"We haven't made any decisions and it's no surprise to any of you that this is an issue in the Unites States of law. We have to meet the requirements of our law," Grossman said.
The Taliban announced this month that it would open a political office in Qatar as a prelude to holding peace talks with the United States and its allies, seen by their supporters as the best chance of ending the decade-long war ahead of a withdrawal of foreign combat troops in 2014.
As a confidence-building measure, the Islamist group called for the release of five officials being held at Guantanamo Bay, a US military enclave and detention centre in Cuba.
But Karzai said on Saturday, after meeting Grossman, that Afghanistan was "not a place for foreigners to do their political experiments", pushing for more Afghan control of the process.
Deputy Foreign Minister Jawed Ludin, standing with Grossman, said the Afghan government was supportive of any process that could end fighting.
There were still many steps to be taken before the opening of a Taliban office in Doha, Ludin said, but the Afghan government had given Grossman support in principle and hoped to bring Qatari diplomats to Afghanistan in the coming weeks to discuss the process.
Grossman has been holding talks with Taliban negotiators for more than a year and his visit could accelerate more talks within weeks now he has the backing of Karzai.