Engaging in peace talks with the Taliban will be an "uneasy endeavour", US Secretary of State John Kerry said, as he thanked Qatar for hosting the group's political office.
Speaking on Saturday at the Friends of Syria meeting in Doha, Kerry said: "We need to see if we can get back on track ... I don't know whether that's possible or not," after these delays this week which saw the Afghan government angry at the fanfare surrounding the opening of the office.
"The road ahead is difficult," Kerry said. "If there is not a decision ... to move forward by the Taliban in short order, then we may have to consider whether or not the office has to be closed."
The opening of the Taliban office was a practical step paving the way for peace talks to end Afghanistan's 12-year-old war.
But the official-looking protocol surrounding the event raised angry protests in Kabul that the office would develop into a Taliban government-in-exile.
A diplomatic scramble ensued to allay the concerns.
Al Jazeera's diplomatic editor James Bays said Kerry's comments were likely aimed at easing the concerns of President Hamid Karzai's government.
"They [US officials] know there is only a small window of opportunity, if they don't do something soon, the Taliban might withdraw their offer to take part."
Initially optimistic about Afghan representatives being dispatched to Doha, Karzai's attitude had abruptly changed by Wednesday. "As long as the peace process is not Afghan-led, the High Peace Council will not participate in the talks in Qatar," Karzai said.
Meanwhile, James Dobbins, the US special representative for Afghanistan and Pakistan, is expected to participate in talks in Doha, but there was some confusion as to who else would take part.
A Taliban spokesman, who asked not to be named, told Al Jazeera that the group had not been told about Dobbins' arrival, and "in light of recent events, we have not yet agreed to have a meeting with the Americans."
He also said that the Taliban is "hopeful" for a solution in due time, but the important issue was "to bring peace to Afghanistan, and remove foreigners occupying our land."
An Afghan diplomat in Doha, speaking to Al Jazeera also on the condition of anonymity, reiterated Karzai's view that peace talks should be "Afghan-led."
US State Department officials have said before that they did not have a timeline for when Dobbins will start potential talks with the Taliban, and have insisted that Kerry himself will not engage in discussions with the rebel group.
President Barack Obama's administration has supported dialogue with the Taliban as the US prepares to pull out its 68,000 combat troops from Afghanistan next year, ending the longest-ever US war which has become increasingly unpopular at home.