The United States and insurgents in Afghanistan have been fighting a war for 12 years, but officials said Tuesday that the U.S. and the Taliban will begin peace talks this week, according to Reuters.

The Taliban opened an office in Doha, the Qatari capital, to help restart talks and said it wanted a political solution that would bring about a just government and end foreign occupation of Afghanistan.

A senior U.S. official said the talks would start in Doha on Thursday, but President Barack Obama cautioned against expectations of quick progress, saying the peace process would not be easy or quick.

U.S. officials say they hope this week's talks will pave the way for the first-ever official peace negotiations between the government of Afghan President Hamid Karzai and the Taliban, which has waged a 12-year insurgency to oust Karzai's government and eject U.S.-led NATO troops from the country.

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U.S. officials said the process could take many years and be subject to reversals.

"This is an important first step towards reconciliation; although it's a very early step," Obama said after a G8 meeting in Enniskillen, Northern Ireland.

"We anticipate there will be a lot of bumps in the road."

U.S. officials said that in the talks in Doha, the United States would stick to its insistence that the Taliban break ties with al Qaeda, end violence, and accept the Afghan constitution, including protection for women and minorities.

U.S. officials said it would be the first U.S. meeting with the Taliban in several years. It was expected to involve an exchange of agendas, followed by another meeting a week or two later to discuss next steps.

A U.S. official said he expected the initial meeting would be followed within days by another between the Taliban and the High Peace Council, a structure set up by Karzai to represent Afghanistan in such talks.

A senior Afghan official said the Taliban had held secret discussions with the Afghan government and were willing to consider talks involving the High Peace Council.

The Taliban have until now said they would not countenance peace talks with the Karzai government, which they consider a stooge of the United States and other Western nations.

In opening the Qatar office, the Taliban said it sought a political solution, but said no dates had been agreed for talks.

"There are no scheduled dates," Tayeb Agha, a former chief of staff to the Taliban's reclusive leader, Mullah Mohammed Omar, said in remarks carried live on al Jazeera television.

Another Taliban representative, Mohammed Naeem, told a news conference at the opening of the Doha office that the Islamist group wanted good ties with foreign countries.

"We want to keep good relations with all of the world countries, in particular with our neighboring countries," he said. "But the Islamic emirate (Taliban) sees the independence of the nation from the current occupation as a national and religious obligation."

Tiny, gas-rich Qatar has been an enthusiastic supporter of reconciliation efforts in a number of political crises and wars affecting the Muslim world including those in Afghanistan, Yemen, Somalia, Lebanon and Darfur, often hosting peace talks on its own soil to try to prove it can punch above its weight in international diplomacy.

The U.S. officials, who spoke on condition of anonymity, said the level of trust between the Afghan government and the Taliban was low, and played down expectations that the talks would quickly lead to peace.

"We need to be realistic," said one official. "This is a new development, a potentially significant development. But peace is not at hand."

News of the planned talks comes as the United States and its allies in NATO seek to meet a deadline of the end of next year for an end to foreign combat operations in Afghanistan.

This would allow them to withdraw the majority of their troops and wind down an engagement launched after the September 11 attacks on the United States in 2001 that has cost hundreds of billions of dollars and tens of thousands of lives.

Obama said peace would only come through an Afghanistan-led process, and commended Karzai for taking a courageous step toward peace. He stressed that the U.S. military effort would continue in spite of the peace efforts.

"We don't anticipate this process will be easy or quick but we must pursue it in parallel with our military approach. And we in the meantime remain fully committed to our military efforts to defeat al Qaeda and to support the Afghan national security forces," Obama said.

Despite the accompanying words of caution, the announcement of the planned talks does represent a significant step forward in the peace process, which has struggled to achieve results despite years of attempts.

A team of envoys from the Taliban flew to Qatar in early 2012 to open talks with the U.S. government. But the Taliban suspended the talks in March 2012, saying Washington was giving mixed signals on the nascent Afghan reconciliation process.

Karzai, speaking on Tuesday as the U.S.-led NATO coalition launched a final phase of security transfers to Afghan forces, said his government would send a team to Qatar, but said the talks should quickly be moved to Afghanistan.

"We hope that our brothers the Taliban also understand that the process will move to our country soon," Karzai said.

U.S. officials said the goal was to ensure that Afghanistan does not remain a haven for terrorism and to defeat al Qaeda.

"The one thing that we do believe is that any insurgent group, including the Taliban, is going to need to accept an Afghan constitution that renounces ties with al Qaeda, ends violence, and is committed to protection of women and minorities in the country," Obama said.

The officials said the United States would want the Taliban to make clear its intention to sever ties with al Qaeda.

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"One of the things we will want to talk about from the very beginning is how they're going to cut ties with al Qaeda," an official said. "How quickly, exactly how they're going to do it, how quickly."

A U.S. official said the talks would be conducted on the Taliban side by its political commission, with the authorization of Mullah Omar, and also represent the al Qaeda-linked Haqqani network. James Dobbins, the new special representative for Afghanistan and Pakistan, will lead the U.S. side.

The Haqqanis are considered the United States' deadliest foe in Afghanistan and the top U.S. and NATO commander in the country cast doubt on Tuesday over whether it could make peace.

"All I've seen of the Haqqani would make it hard for me to believe they were reconcilable," U.S. General Joseph Dunford told Pentagon reporters by phone from Kabul.

U.S. officials said they expected detainee exchanges to be discussed in the talks. The United States will ask for the safe return of U.S. Sergeant Bowe Bergdahl, who has been a prisoner since June 2009, the officials said. He is thought to be being held by Taliban militants in northwestern Pakistan.

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