Pakistan’s release late last year 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.

American, Afghan and Pakistani officials say they believe some of the freed Islamist movement members have rejoined their colleagues waging war against Western troops and the coalition-backed government of Afghan President Hamid Karzai.

With its long-standing links to Afghan Taliban insurgents, Pakistan has a vital role in nudging them to the table as the United States winds down its involvement in the 11-year war in Afghanistan. But 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 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 ­Inter-Services Intelligence, or ISI, as part of a road map drawn up by the Afghan High Peace Council to build the militants’ confidence.

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.

The U.S. 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.

‘Back to their old ways’

“It’s all a black hole,” one U.S. official said, speaking on the condition of anonymity because of the sensitivity of the issue.

A Pakistani security official confirmed that 18 men were freed and described them as junior to mid-level members of the Islamic movement, including field commanders and foot soldiers.

“Some have gone back to their old ways, with their old friends,” said the official, who also spoke on the condition of anonymity.

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 most senior of the captives, Noruddin Toorabi, the ailing former justice minister in the Taliban government, has promoted himself as a spokesman for the collective prisoners. But, like others set free, he will have to be anointed by Taliban chief Mohammad Omar to be allowed a role in any prospective peace talks.

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, said the Pakistani security official, “Baradar isn’t going anywhere anytime soon.”

Rabbani, in an interview, 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 neighbors. The idea was to cement their common interest in averting a civil war in Afghanistan after the United States pulls out its combat troops at the end of 2014.

It hasn’t 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?

Unclear effect

“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.

Meanwhile, the Taliban continues to assert that it will never negotiate with Karzai, whom it considers an illegitimate leader and U.S. puppet.

This week, Taliban spokesman Zabiullah Mujahid scoffed at talks in London held by Karzai, Pakistani President Asif Ali Zardari and British Prime Minister David Cameron aimed at bringing the Taliban to the table. In a statement, Mujahid said previous contacts with “counterfeit and ineffective individuals and circles” had led nowhere — a glancing repudiation of the prisoner releases.

Omar Samad, a former diplomat under Karzai, said the prisoners’ release has not resulted in any progress toward resumption of talks, which are already bogged down by competing interests and rival back-channel negotiations among several countries including the United States, which has angered Karzai by making separate overtures to the Taliban.

“Different agendas are playing out,” Samad said. “And the clock is ticking.”

Sieff reported from Kabul.