The Obama administration is pressing the Afghan government to sign a new security pact or face the prospect of no U.S. troops in the country beyond 2014.
In an interview with VOA's Afghan Service Friday, State Department spokeswoman Jen Psaki said "the bottom line is we need to conclude this agreement with a signature between our two governments as quickly as possible and certainly by the end of the year."
Psaki said if that does not happen, it "makes it nearly impossible" for the United States and its allies to plan for a troop presence after 2014.
Psaki's comments come after a spokesman for Afghan President Hamid Karzai insisted Friday -- in a direct rebuff to the U.S. -- that the pact will be signed only after presidential elections scheduled for April.
A national assembly of tribal, community and elected leaders, known as a Loya Jirga, is meeting this week in Afghanistan to discuss the pact.
About 2,500 local and regional leaders are participating in the Loya Jirga, which has broken into small groups to study the proposed agreement item by item.
Most are believed to favor the deal, which spells out terms under which international forces would remain in the country to assist the government in its war against Taliban insurgents.
But U.S. officials were stunned Thursday when Mr. Karzai suggested that the formal signing of the pact could be put off until the middle of next year, when he will be out of office.
White House spokesman Josh Earnest stressed the importance of having the agreement signed this year so that long-term planning can begin. He noted the United States has not yet made a final decision on whether to keep its troops in Afghanistan.
But Karzai spokesman Aimal Faizi said Friday the Afghan government is not impressed by U.S. deadlines. He repeated that the signing -- if there is one -- would take place after the April elections.
Mr. Karzai opened the assembly Thursday with an impassioned speech in support of the pact, saying it has the support of Afghanistan's major allies and neighbors except Iran.
The deal is to take effect January 1, 2015 and will keep U.S. troops and civilian personnel in Afghanistan for at least another decade and possibly even longer.
During his speech, Mr. Karzai read out parts of a letter from U.S. President Barack Obama that promised the United States will continue to "respect the sanctity and dignity of Afghans in their homes" under the new security agreement.
Mr. Obama's letter, released by the Afghan government, also said many Americans have died or been seriously wounded in an effort to help and protect the Afghan people.
A draft text of the agreement said U.S. troops will only enter Afghan homes in exceptional cases -- a point of contention in nearly a year of negotiations on the agreement.
The Jirga is expected to spend several days debating the pact, which will shape the security relationship between Washington and Kabul for years to come. The group must give its approval before the document goes to the Afghan parliament for a vote.