of several imprisoned Taliban officials and fighters, which it advertised as a good-faith effort to help bring peace to Afghanistan, is now prompting questions about whether the gesture has yielded anything but potential new dangers for NATO and Afghan troops," the Washington Post quoted American, Afghan and Pakistani officials as saying.
"It's all a black hole," one US official said, speaking on the condition of anonymity.
A Pakistani security official confirmed that 18 men were freed and described them as junior to mid-level Taliban members, including field commanders and foot soldiers.
"Some have gone back to their old ways, with their old friends," said the unnamed official.
Pakistan's handling of the prisoner release once again subverted the trust of the Afghans, who were supposed to receive the captives and keep tabs on them to lower the risk of any returning to terrorist havens in Pakistan, the report said.
The whereabouts and even the number of ex-prisoners have remained murky since their release in two batches in mid-November and late December by Pakistan's powerful spy agency, the ISI, as part of a road map drawn up by the Afghan High Peace Council to build the militants' confidence, it said.
Despite an earlier agreement, the ISI failed to consult with the council when it set many of the captives free. On Friday, however, the Pakistani government pledged to coordinate future Taliban releases with the council, in a belated admission that it had blindsided the Afghans, it said.
The US military is keenly interested in the former captives' whereabouts and is trying to track down any who have returned to the Taliban in Afghanistan — and wants to identify those participating in the reconciliation process so they won't be targeted.
The original deal, presented in Islamabad by peace council head Salahuddin Rabbani and backed by Washington, envisioned the prisoners being handed over to Afghanistan or a third country.
Instead, most of the released Taliban members rejoined their families in Pakistan, in cities including Quetta, Peshawar and Karachi, to recover from years in detention, according to residents and a Taliban spokesman.
The ISI spurned a specific request by Rabbani to free the most important prisoner: Abdul Ghani Baradar, the deputy leader under Omar taken captive in 2010.
Afghan officials considered Baradar's release a crucial olive branch to Omar to nudge along a mediated end to the war.
But the Pakistani security official said, "Baradar isn't going anywhere anytime soon."
Rabbani acknowledged that questions remain about the ability of any Taliban representatives to negotiate on behalf of a group that he says is splintered. But he said he remains an optimist.
"You can't convince everyone in the opposition to join the peace process," he said, "but if you can convince a large majority, the level of violence will come down."
Part of the Afghan government's goal in giving Pakistan a key role in brokering any deal was to allay enmities between the ever-suspicious neighbours. The idea was to cement their common interest in averting a civil war in Afghanistan after the US pulls out its combat troops at the end of 2014.
It has not worked out exactly that way, given the friction over the prisoner releases including the fact that the peace council got only two of the four specific prisoners it asked for.
The motives of the ISI in releasing hand-picked captives remains unclear, and probably deliberately so, analysts said: Was it to help the peace process, as claimed, or to keep its Taliban proxies on the field to assure Pakistan's influence in any future Afghan government?
"This is not for Afghanistan, it's for Pakistan's game," said Wahid Mujda, a former Taliban government official who closely monitors peace overtures.
Mujda said he doubted the releases would have any impact on negotiations because "the important people are still in jail," including Baradar.
Omar, who headed the Taliban regime during its five-year rule, has conditioned negotiations on the release of five Taliban leaders held at Guantanamo Bay and a permanent withdrawal of all foreign troops.