The United States and Afghanistan worked to finalize a crucial security pact on Wednesday, a day before more than 2,500 Afghan elders are due to begin debating whether to allow some U.S. troops to stay in the country after 2014.
Just before midnight local time, the Afghan Foreign Ministry posted what appeared to be a draft of the agreement on its website.
The U.S. State Department said later that discussions were still under way and that it was reviewing the draft. In Kabul, an Afghan official with knowledge of the talks said he expected a deal to be struck later in the night.
Afghan President Hamid Karzai negotiated the draft agreement with U.S. officials, but the tribal assembly, or Loya Jirga must give its approval before the document goes to the Afghanistan parliament for a vote.
A key sticking point is whether Washington will agree to offer assurances that U.S. troops will enter Afghan homes only in "exceptional" circumstances to save lives.
The issue gained attention Tuesday after Afghan presidential spokesman Aimal Faizi said the two sides had agreed to allow home raids if President Barack Obama writes a letter acknowledging mistakes by the U.S. military in Afghanistan.
The Afghan government said it had received assurances that a letter from Mr. Obama would be provided this week to the Jirga.
But National Security Adviser Susan Rice told CNN television Tuesday there is "no need" for the United States to apologize to Afghanistan.
Kabul remains on high alert with offices closed and dozens of checkpoints set up along the route leading to the site of the three-day gathering of Jirga delegates, including tribal, political and intellectual leaders.
The so-called Bilateral Security Agreement is seen as vital to lasting peace in the war-torn nation, where the United Nations said the Taliban insurgency this year reached levels of violence not seen since 2010.
Also Wednesday, Afghanistan's election commission announced the final list of candidates for next year's presidential poll, which will be the country's first-ever democratic power transfer.
Mr. Karzai, appointed following the U.S.-led invasion of 2001, must step down after serving two terms.