ABU DHABI - Pakistan plans to release all Afghan Taliban prisoners still in its detention, including the group's former second-in-command, an official said on Friday, in the clearest signal yet that it backs reconciliation efforts.Regional power Pakistan is seen as critical to the success of US and Afghan efforts to bring stability to Afghanistan, a task gaining urgency as the end of the US combat mission in 2014 draws closer.Afghanistan has been pressing its neighbour, home to an allied Taliban movement of its own, to free Taliban members who could help promote its tentative reconciliation efforts."The remaining detainees, we are coordinating, and they will be released subsequently," Jalil Jilani, Pakistan's foreign secretary, the foreign ministry's top bureaucrat, told a news conference in Abu Dhabi.Asked if the former Taliban deputy leader, Mullah Baradar, would be among those released, he said "The aim is to release all", but did not elaborate further.Jilani was speaking after meeting the acting US special representative for Afghanistan and Pakistan, David Pearce, and Afghan Deputy Foreign Minister Jawed Luddin at the Afghan embassy in Abu Dhabi. Luddin told reporters the purpose of the meeting was to discuss "security and political dimensions of bilateral relationships" between the three countries.The Taliban seized power in Afghanistan in 1996 and were toppled by US-backed forces in 2001. Many Afghans fear they will make a renewed push to seize power once Western forces pull out.Mutual suspicions between Afghanistan and its nuclear-armed neighbour have hampered efforts to tackle militancy in one of the world's most explosive regions. Luddin said the peace process had gained momentum in recent weeks with the release of some Taliban detainees by Pakistan, preparations by the Afghan Taliban movement to open a political office in Doha, and Afghan President Hamid Karzai's visit to Washington."Steps have been taken forward in an environment of cooperation and shared concerns ... 2013 is a very crucial year and we agreed we need to maintain the momentum," he said. "2013 will see concrete outcomes in the peace process."At their meeting a week ago, Karzai and US President Barack Obama agreed to speed up the handover of combat operations in Afghanistan to Afghan forces, raising the prospect of an accelerated US withdrawal.Karzai also appeared to give ground on US demands for immunity from prosecution for any American troops who stay in Afghanistan beyond 2014, a concession that could allow Obama to keep at least a small residual force there.