The United States will meet the Taliban in Doha in a couple of days for talks aimed at achieving peace in Afghanistan, where the United States has battled the insurgents for 12 years, U.S. officials said on Tuesday.

The officials, who spoke on condition of anonymity, warned that the process would likely be lengthy.

They said the Taliban would issue a statement on Tuesday opposing the use of Afghan soil for attacks on other countries and that they support an Afghan peace process.

A senior Afghan official on confirmed the Taliban is considering peace talks with the Afghan state following secret discussions.

"We hope that the attacks carried out by the Taliban in Afghanistan will reduce while we talk peace; there is no point in talking if the bombs continue to kill civilians," he said.

However, a senior Taliban official said later in the day that no date had been set for the talks. Asked by a reporter whether a date had been set, Tayeb Agha replied: "There are no scheduled dates."

The remark by Agha, the former chief of staff to the Taliban's reclusive leader, Mullah Mohammed Omar, was carried live on Al-Jazeera television.

If the talks take place, the United States will insist the Taliban break ties with Al-Qaeda, end violence, and accept the Afghan constitution, including protection for women and minorities, the officials told reporters in a conference call.

"This is but the first step in what will be a long road," one U.S. official said.

The first formal meeting involving U.S. and Taliban representatives is scheduled to be later this week in Doha, the U.S. officials said. Talks between the Afghan government and the Taliban are expected to take place a few days after that, they said.

Drawn-out process

U.S. officials 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. The talks were likely to be subject to reversals and could take many years, one official said.

"Peace is not at hand," the official 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 talks will be conducted on the Taliban side by its political commission, with the authorization of Taliban leader Mullah Mohammed Omar, a U.S. official said. The commission would also represent the Al-Qaeda-linked Haqqani network, which is considered the United States' deadliest foe in Afghanistan.

Officials said they expect detainee exchanges to be on the agenda. 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.

The first U.S.-Taliban meeting is expected to be an exchange of agenda, followed by another meeting a week or two later to discuss next steps, the U.S. officials said.

The planned talks follow discussions between President Barack Obama and Afghan President Hamid Karzai in January, officials added.

Security transition 

The announcement came on the same day that the Taliban opened their long-delayed office in the Qatari capital of Doha.

Taliban official Mohammed Naeem announced the opening of the office in a press conference in Doha.

In a move that may anger the Afghan government, the white Taliban flag was at his side, and a large sign behind him proclaimed the office of the "Islamic Emirate of Afghanistan", the name the Taliban used during their brief national rule in the 1990s.

Both events may have been timed to coincide with a ceremony on Tuesday to mark the beginning of the final phase of security transition from the U.S.-led coalition to the Afghan state.

Fear is mounting that Afghanistan could fall into chaos following the pullout of most NATO combat troops by the end of 2014. A presidential election is also due that year.

NATO and its partners are training Afghanistan's 352,000-strong security forces, though questions remain over how ready they are to tackle the insurgency on their own.