The Afghan government says it had reached a deal on the framework of a security pact with the United States after receiving assurances that President Barack Obama would issue a letter acknowledging U.S. mistakes made during the 12-year war.

In Washington, White House and State Department officials wouldn't confirm whether Mr. Obama would send such a letter.  White House press secretary Jay Carney said he wouldn't comment on a “letter that hasn't been written.”

Obama's letter to Afghan President Hamid Karzai would “mention that there were mistakes made in the conduct of military operations by US forces in the past decade, and that the Afghan people have suffered, and we understand their pain, and therefore can give assurances that these mistakes will not be repeated," said Karzai’s spokesman Aimal Faizi.

It is a last-minute compromise for a US government that had ideally wanted this deal signed months ago, so that US forces could plan for the period after combat operations end in 2014.

If that letter comes, the deal will then be presented for approval by the Loya Jirga, a gathering of as many as 3,000 Afghan tribal leaders later this week.