KABUL, Afghanistan (AP) -- Infuriated that Washington met secretly at least three times with a personal emissary of Taliban leader Mullah Mohammed Omar, the Afghan government intentionally leaked details of the clandestine meetings, scuttling the talks and sending the Taliban intermediary into hiding, The Associated Press has learned.

In a series of interviews with diplomats, current and former Taliban, Afghan government officials and a close childhood friend of the intermediary, Tayyab Aga, the AP learned Aga is hiding in Europe, and is afraid to return to Pakistan because of fears of reprisals. The United States has had no direct contact with him for months. The Skanner News Video: US troops in action

A senior U.S. official acknowledged that the talks imploded because of the leak and that Aga, while alive, had disappeared. The United States will continue to pursue talks, the official said. Current and former U.S. officials spoke on condition of anonymity because they were not authorized to discuss the talks.

The United States acknowledged the talks after Afghan President Hamid Karzai, who apparently fears being sidelined by U.S.-Taliban talks, confirmed published accounts about them in June, but has never publicly detailed the content, format or participants. The first was held in late 2010 followed by at least two other meetings in early spring of this year, the former U.S. official said. The sessions were held in Germany and Qatar, he said.

A childhood friend of Aga's who spoke to the AP on condition he not be identified because he feared retaliation, said Aga was in Germany. A diplomat in the region said Aga fled to a European country after his contacts with the United States were revealed.

Collapse of the direct talks between Aga and U.S. officials probably spoiled the best chance yet at reaching Omar, considered the linchpin to ending the Taliban fight against the U.S.-backed government in Afghanistan. The contacts were preliminary but had begun to bear fruit, Afghan and U.S. officials said.

Perhaps most importantly they offered the tantalizing prospect of a brokered agreement between the United States and the Taliban - one that would allow the larger reconciliation of the Taliban into Afghanistan political life to move forward. The United States has not committed to any such deal, but the Taliban wants security assurances from the United States.

The talks were deliberately revealed by someone within the presidential palace, where Karzai's office is located, said a Western and an Afghan official. The reason for the leak was Karzai's animosity toward the U.S. and fear that any agreement Washington brokered would undermine his authority, they said.

The AP sought comment from Karzai's office but was referred to palace press department spokesman Hamid Elmi, who did not answer his phone during repeated calls.

Pakistan had also been kept in the dark about the talks, people knowledgeable about them said. An Afghan official with contacts with the Taliban said the insurgents decided not to tell Pakistan about the meetings with the United States.

At the time of the leak, Washington had already offered small concessions that the U.S. intended as "confidence-building measures," a former senior U.S. official said. They were aimed at developing a rapport and moving talks forward, said a current U.S. official on condition he not be identified because of the sensitivity of the topic.

The concessions included treating the Taliban and al-Qaida differently under international sanctions. The Taliban argued that while al-Qaida is focused on worldwide jihad against the West, Taliban militants have focused on Afghanistan and have shown little interest in attacking targets abroad.

Other goodwill gestures that were not made public included Aga's safe passage to Germany, U.S. officials said. The U.S. also offered assurances that it would not block the Taliban from opening an office in a third country, the official said.

Aga slowly established his bona fides with the U.S. officials, who had initial doubts both about his identity and his level of contact and influence with Omar, a former and current U.S. official with knowledge of the discussion said. For example, a coded reference to the talks appeared on a Taliban-affiliated website following one meeting, just as Aga said it would, one official said.

The whereabouts and eventual release of U.S. Army Sgt. Bowe Bergdahl of Hailey, Idaho, who was captured more than two years ago in eastern Afghanistan, featured prominently in the talks, according to Aga's childhood friend and a senior Western diplomat in the region. The U.S. negotiators asked Aga what could be done to gain Bergdahl's release.

Aga sought the freedom of Taliban fighters in U.S. custody in Guantanamo Bay and Bagram Air Field, north of the Afghan capital where an estimated 600 Afghans are being held. Still at Guantanamo Bay is former Taliban Defense Ministry Chief of Staff Mullah Mohammed Fazil, Taliban intelligence official Abdul Haq Wasiq and former Herat governor Mullah Khairullah Khairkhwa. Afghanistan's High Peace Council tasked by Karzai with the job of finding a negotiated settlement with insurgents has requested Khairkhwa's release.

A former U.S. official familiar with the talks said the loss of the Aga contact dismayed and angered the U.S. side, and further eroded thin trust in Karzai. There is a difference of opinion among U.S. diplomats, military officials and others about how directly Karzai should be blamed, but several officials agreed that the leak was an attempt to torpedo a diplomatic channel that Karzai and his inner circle worried would sideline and undercut the Afghan leader.

As the Afghan war slides into its 10th year and Washington plans to withdraw its combat forces by the end of 2014, a negotiated settlement between the Karzai government and the Taliban has become a stated goal for the United States. It is the centerpiece of efforts by Marc Grossman, the U.S. special envoy to Afghanistan and Pakistan.

Karzai has launched a separate peace outreach, with the High Peace Council representing numerous political factions.

A member of that High Peace Council, who asked not to be identified by name so he could talk candidly, told the AP that the leaking of the talks reveals the level of mistrust and the lack of coordination among the key players in any eventual peace deal.

He said all the key players - the United States, Afghan government, Afghan National Security Council and the High Peace Council - are holding separate and secret talks with their own contacts within the insurgency.

The United States, for example, has also held secret talks with Ibrahim Haqqani, the brother of Jalaluddin Haqqani, who heads the notorious Haqqani network considered by U.S. and NATO troops in Afghanistan to be their biggest threat. That contact was confirmed by officials from Pakistan, Afghanistan and the U.S.

Karzai met with representatives of wanted rebel leader Gulbuddin Hekmatyar, who is seeking greater involvement at the peace table and direct talks with the United States, said diplomats in the region.

The flurry of meetings the United States is holding with the various factions in the Afghan conflict has also extended to Pakistan, where the most powerful insurgents have found safe havens.

A month ago, U.S. Senate Foreign Relations Committee Chairman Sen. John Kerry and Pakistan's Army chief of staff Gen. Ashfaq Pervez Kayani met for a marathon eight hours in a Gulf country. Peace negotiations with Afghanistan's insurgents featured prominently, said both Pakistani and U.S. officials who would not be identified by name because of the secret nature of the meeting.

A U.S. official familiar with the talks said Kayani made a pitch during his marathon meeting with Kerry that Pakistan take on a far larger role in Afghanistan peacemaking. The United States considers Pakistan an essential part of an eventual deal, but neither the U.S. nor Pakistan trusts the other's motives in Afghanistan.

Meanwhile, an unexpected consequence of attempts to find peace with the Taliban has been the rearming of the so-called Northern Alliance, that represents Afghanistan's ethnic minorities and who were partnered with the coalition at the outset of Operation Enduring Freedom to topple the Taliban regime.

For the warlords that make up the Northern Alliance, Martine van Bijlert, co-director and co-founder of the Afghan Analyst Network in the capital, Kabul, talk of peace threatens their survival.

Warlords-cum-government ministers and vice presidents are watching attempts at finding a peaceful end to the war with trepidation, each wondering "what if it unravels, who is going to come after me? Will I be the weakest in the room? They are feeling very vulnerable."

Gearan, AP National Security Writer, reported from Washington. Kathy Gannon is AP Special Regional Correspondent for Afghanistan and Pakistan. She can be followed on http://www.twitter.com/kathygannon