Afghan Taliban deny Mullah Omar wrote to White House

KABUL (Reuters) - The Afghan Taliban denied on Saturday that the group's leader Mullah Omar wrote to the White House last year.

The White House received a letter in 2011 which purported to come directly from Mullah Omar, asking the United States to deliver prisoners whose transfer is now central to American efforts to broker peace in Afghanistan, an Obama administration official said Friday.

"Islamic Emirate of Afghanistan rejects this baseless rumor with the strongest of words," a statement on the Islamist group's website said, using the name by which the Taliban often calls itself.

The letter, intended for President Barack Obama, reportedly expressed impatience that the White House had not transferred five former senior Taliban officials out of Guantanamo Bay military prison.

The White House itself was "skeptical" the letter was actually from Mullah Omar, the official said, though others within the administration believed it was authentic.

"Hoping for surrender from the Afghan people is an unrealistic wish and a goal which could not be achieved by America in the past ten years," said Saturday's statement, attributed to Taliban spokesman Zabihullah Mujahid.

The Taliban last month said it would open a political office in Qatar, suggesting the group may be willing to engage in negotiations.

After more than a decade of war, Washington and its allies are announcing plans to steadily withdraw their troops amid doubts about the ability of the Afghan government and its nascent security forces to confront ongoing violence.

This week, U.S. Defense Secretary surprised Kabul by suggesting the American combat mission could end in 2013, well ahead of the end-2014 deadline agree with Afghan President Hamid Karzai for the exit of foreign combat troops.

"The U.S. is committed to the Lisbon timetable, which means that combat operations by international and Afghan forces are fully resourced and capable as necessary until the end of 2014 and beyond," U.S. ambassador to Afghanistan Ryan Crocker said in a statement Saturday.

"This is not a change in policy or strategy but recognition of the progress we all agreed to achieve in Lisbon."

(Reporting by Daniel Magnowski; Editing by Jonathan Thatcher)