The fallout from the burning of Qurans at a US base has complicated already troubled negotiations about the nature of the US-Afghan relationship once NATO combat troops leave in two years' time.
At stake is a strategic partnership deal covering the period after 2014 when the US-led coalition is due to pull out combat troops and hand responsibility for security to the Afghan government.
President Hamid Karzai has used the burnings to reiterate a series of demands to be met before he signs a long-term treaty, while the US embassy has since signalled the possibility that no agreement will be reached.
"We have always said it is more important to get the right agreement than to get an agreement," US embassy spokesman Gavin Sundwall said.
In Iraq, Washington abandoned its pursuit of a strategic partnership deal and pulled all its troops out after failing to get the government to confer legal immunity on the troops.
Karzai told a joint news conference with visiting Polish President Bronislaw Komorowski on Tuesday that his government was "working with the United States" on the conditions for a deal.
"We had a meeting yesterday and we had questions and we demanded clarity, and progress was made," Karzai said, in an apparent reference to talks with US ambassador Ryan Crocker.
The US embassy would not comment on the meeting, or even confirm it had taken place.
One of Karzai's main demands -- in the name of Afghan sovereignty -- is for Afghans to take control soon of the US-run prison at Bagram military base north of Kabul, where the Qurans were sent to an incinerator pit.
When a first deadline of early February was missed, Karzai gave the US one more month to transfer the jail -- known as Afghanistan's Guantanamo Bay -- but that looks increasingly unlikely.
Sundwall insists the US is committed to the transition "in a manner that is safe and orderly and in accordance with our international legal obligations".
Another sticking point is whether the US will have permanent bases in Afghanistan. Despite America insisting it does not want this, a US official has told AFP that any arrangement would probably involve "shared facilities" in order to help Afghan forces with intelligence, air power and logistics.
The Quran burning ignited days of violent anti-US protests in which some 40 people died, plunging relations between foreign forces and their Afghan allies to an all-time low and forcing US President Barack Obama to apologise.
But while the protests died out a week ago, some analysts suspect Karzai is trying to keep the issue alive as a bargaining chip in talks over a long-term deal with Washington.
"I think he feels it has strengthened his position," said Martine van Bijlert of the Afghanistan Analysts Network.
"My sense is that this was a complicated negotiation to start with. It has been made more complicated by the Quran burning and the frayed relationships, but it would have never been easy.
"What makes it even more complicated is the fact that the news that comes out about the negotiations is also part of the game, with each side trying to put more pressure on the other."
Five days after the protests ended, Karzai's office issued a statement by the government-funded Ulema Council, the country's top religious body, which called for the public trial of the perpetrators -- and again pressed for the handover of Bagram.
"I believe Hamid Karzai is using this council to pressure Americans to give in to his demands for a bigger role in peace talks with the Taliban in Qatar as well as other demands," Afghan author and analyst Ahmad Saeedi told AFP.
Karzai was widely reported to have felt sidelined by Washington's tentative contacts with Taliban insurgents -- and his first Bagram deadline was set just days after they were revealed in early January.
The Taliban have always spurned the idea of talking to Karzai's government, saying it is a US puppet, but control of Taliban detainees in the Bagram prison could give his government new cards to play.
The events surrounding the Quran burning marked "a watershed" in relations between Afghanistan and the West, said veteran Afghan watcher and best-selling author of a book on the Taliban, Ahmed Rashid.
The United States was likely to stick to its plan to pull all combat troops out of the country in 2014, but its commitment after that would come under review, he predicted.