US Secretary of State Hillary Clinton arrived in Kabul on an unannounced visit on Saturday on the eve of a major conference in Tokyo in which Afghanistan is set to seek billions of dollars in civilian aid.
"Considering that we are almost literally flying by, the secretary wanted to be able to stop in Kabul en route to Tokyo, in large part just to check signals before this last major, significant ministerial conference," a senior State Department official told reporters travelling with Clinton.
The top US diplomat was to hold breakfast talks with Afghan President Hamid Karzai at the presidential palace in Kabul.
Karzai, who will be in Tokyo along with officials including Clinton and United Nations chief Ban Ki-moon, has called for some $4 billion a year in civilian aid for Afghanistan to be pledged during Sunday's conference.
The World Bank has estimated that Afghanistan will need some $3.9 billion a year in civilian assistance for its aid-dependent economy, amid fears donations could dry up when NATO pulls out in 2014.
But a principle of "mutual accountability" will be stressed at the 70-nation meeting, making continued payment of aid conditional on Kabul making progress, particularly on transparency.
"The international community will continue to come together and show this enduring commitment that will be at or near levels that we've used over the past decade," the US official said, asking to remain anonymous.
He refused to be drawn on what the specific level of aid pledged by the United States would be, saying the amount would remain at current levels.
In the fiscal year 2012 the US civilian aid commitment was "particularly high" at $2.3 billion, he said. But in 2003 it was at $1 billion.
Negotiators were also said to be still hammering out a time period over which the funding would continue.
"Whilst (the NATO summit in) Chicago sought to show the beginnings of the implementation into transition, the transformation decade, on the security side, the goal of Tokyo is to (do) that same piece on the economic side, the civilian side," the official said.
"This will be more specific about the ongoing commitment of the international community to economic development and the civilian assistance piece writ large."
He stressed the important role of the private sector and encouraging private sector investment.
"For true kind of economic stability which obviously goes hand in hand with political stability there's obviously a diminishing role for assistance over time if we can build up true economic investment," he said.
After more than 30 years of war, the Afghan economy is weak and the country cannot survive without foreign aid. According to the World Bank, spending on defence and development by donors accounted for more than 95 percent of GDP in 2010-11.
Without a functioning economy, Kabul covers only $2 billion of the $6 billion it spends each year not counting security costs, said a Western diplomat, with donor countries making up the difference.
That would add to the $4.1 billion promised annually at the Chicago conference in May for security costs.
The Western diplomat said the Afghans were terrified that when NATO pulls out, the money will disappear with them.
Sources expect a deal worth up to $3.9 billion a year to be agreed in Tokyo, but after more than 10 years of sacrificing soldiers and tax dollars to the Afghan cause, leading donors are proving hard to persuade.
Japanese Foreign Minister Koichiro Gemba, who will jointly chair the Tokyo conference, said he was hoping it would result in pledges worth at least $3.0 billion a year.
But in an interview with the Asahi Shimbun newspaper published Friday, he also warned of conditions for Karzai's government.
"(Kabul) must improve its governance capacity, including eradicating corruption," he said, adding a mechanism to review progress in these areas every two years had to be developed.
Clinton will also hold a core group ministerial meeting for the first time in Tokyo, with her Pakistani and Afghan counterparts.