Pakistani officials said Tuesday that they would release a senior Afghan Taliban leader who has been held for three years , raising limited hopes for a breakthrough in troubled peace negotiations between Taliban insurgents and the Afghan government.

Afghan officials responded cautiously to the news, saying they want to ensure that they have access to the detainee, Abdul Ghani Baradar, once he is released. Baradar, a founder of the Islamist Taliban movement, is known to have relatively moderate views and to strongly advocate talks to end the decade-long conflict.

Afghan and Pakistani analysts, meanwhile, said releasing him would have little effect on the peace process unless he receives the unlikely blessing of the Taliban’s fugitive supreme leader, Mohammed Omar.

Omar, who is thought to live in Pakistan, has been known to have major differences with Baradar.

The decision was revealed by Sartaj Aziz, a senior national security adviser to Pakistani Prime Minister Nawaz Sharif. Aziz told a BBC interviewer in Islamabad on Tuesday that Baradar “could be released this month or very soon,” describing the gesture as “part of confidence-building measures.” Aziz added, “We are hopeful he can play a role.”

Sartaj Aziz, a senior national security adviser to Pakistani Prime Minister Nawaz Sharif, said Abdul Ghani Baradar “could be released this month or very soon,” describing the gesture as “part of confidence-building measures.” (Faisal Mahmood/Reuters)

In Kabul, the chief spokesman for President Hamid Karzai said the government welcomed the news but was concerned that Pakistan had not indicated that it would hand the veteran insurgent over to Afghan authorities. Aziz said Baradar would be sent wherever he wanted to go.

“We would like him to be accessible, have an address and be provided with security,” Karzai’s spokesman, Aimal Faizi, said in a brief telephone interview Tuesday night. He said Afghan officials and members of the country’s High Peace Council would like to speak to Baradar about peace talks.

Faizi said officials in Kabul think Baradar can play a “positive and important role” in reviving the negotiations, despite being isolated from other Taliban leaders and field commanders while in prison.

Aziz’s announcement came two weeks after Karzai traveled to ­Islamabad to seek the help of Sharif and other officials in reviving the peace talks. Baradar’s release reportedly was one of Karzai’s main requests, but Pakistan responded last week by releasing seven lower-ranking Taliban prisoners.

Baradar, 45, was captured in Karachi, Pakistan, in February 2010 in a joint U.S.-Pakistani intelligence operation. Many Afghans contend that he was detained because he was attempting to promote a secret, independent peace track that Pakistan wanted to thwart to gain more control over the process. The Karzai government has long accused Pakistan of covertly trying to destabilize Afghanistan.

Members of the Afghan High Peace Council, established several years ago to negotiate with the Taliban, expressed a mixture of optimism and caution at the news that Baradar would be freed.

One member, Mohammad Ismail Qasimyar, said Baradar has been willing to help bring peace to Afghanistan. “Because of that, they put him in jail,” Qasimyar said. “I believe it is good for both Afghanistan and Pakistan to build trust, and this release is important.”

But Abdul Hakim Mujahid, another member and a former diplomatic representative of the Taliban when it ruled most of Afghanistan from 1996 to 2001, said Baradar’s release would have “limited impact” unless his promotion of peace talks won Omar’s support.

This is very good and important news. He can play an important role in the peace process if he does it in consultation with the Taliban leadership,” Mujahid said. “But if he plays that role as an independent alone, that would be a little problematic. For now, the best thing would be to wait and see.”

Muhammad Amir Rana, director of the Pakistan Institute for Peace Studies in Islamabad, said Kabul was eager for Baradar’s release because “no other Taliban leader is willing to talk to Afghan authorities.” But he, too, said he doubted that Baradar would be able to “win back the confidence” of Omar after having struck out independently to advance peace talks before his arrest.

Pakistan has released more than 30 Taliban prisoners this year, but none has since played a public role in the peace process, which has been plagued by disputes and mistrust. The Islamabad government, which previously backed the Taliban, now appears more eager to pursue a peace settlement because of fears that Afghanistan might descend into civil war and chaos after U.S. forces withdraw next year.

Although the Karzai government has pushed hard for the Taliban releases, it also worries that the freed insurgents will return to armed conflict. In Baradar’s case, Afghans appear to have more confidence in his motives and reportedly hope that he might open a new negotiating site, in Turkey or Saudi Arabia.

A U.S.-backed attempt to set up a Taliban office in Qatar fell apart in June after a dispute over whether the insurgents would be allowed to display the flag and title of their former regime, “The Islamic Emirate of Afghanistan.”

Sayed Salahuddin in Kabul and Shaiq Hussain in Islamabad contributed to this report.