Haqiq was arrested by the US and Afghanistan intelligence agents from a secret location in Afghanistan in June 2007. He was one of the high-profile Afghan Taliban spokesmen along with Yousuf Ahmadi, appointed after chief spokesman Abdul Latif Hakimi was arrested in October 2005 in Pakistan.
With the US expected to begin withdrawing troops from Afghanistan in July, Washington has stepped up the pace of talks with Taliban leaders.
During a visit to Pakistan last month, US Special Envoy to Afghanistan and Pakistan Marc Grossman had reportedly appealed for help in contacting the reclusive Taliban leader.
Earlier, in February, US Secretary of State Hillary Clinton had also signalled a sea change in the Obama administration policy when she compared talking with the Taliban to former US president Ronald Reagan's decision to "sit down with the Soviets".
During a trip to the region earlier this month, the outgoing US Defence Secretary Robert Gates had predicted that talks would start "by the end of the year".
