US Secretary of State Hillary Clinton has made a pledge to continue Afghan aid at its current levels until 2017, as some 70 countries gathered in Tokyo to announce a four-year civilian assistance plan.
Altogether, the countries promised on Sunday to give $16bn to Afghanistan through to 2015.
The White House will ask Congress to sustain US assistance for Afghanistan near the average amount it has been over the last decade through 2017 as part of the international effort to stabilise the country, even as most international forces pull out over the next two years.
The funds would help Afghanistan build its economy and make necessary reforms, Clinton said.
"We have to make the security gains and the transition irreversible,'' Clinton told officials, including Afghan President Hamid Karzai.
She said Afghan security "cannot only be measured by the absence of war".
These statements at the Tokyo summit came shortly after roadside bombs killed 35 people, including seven Nato soldiers, in Afghanistan's southern Kandahar province close to the Pakistan border.
Provincial police chief General Abdul Raziq blamed the attack on Taliban fighters who have been waging a decade-long campaign to topple Karzai's government.
The deaths come a day after bomb blasts and a rocket attack in southern Afghanistan killed 11 civilians, including at least four children, in a space of 24 hours.
These attacks add to fears about security as NATO prepares to hand responsibility to Afghan forces and recall the vast majority of its 130,000 combat troops by the end of 2014.
A US diplomat said the money will come with conditions to ensure it does not fall victim to rampant Afghan corruption and mismanagement.
"It has to be measured by whether people have jobs and economic opportunity; whether they believe the government is meeting their needs,'' Clinton said.
Clinton said Afghanistan has made substantial progress over the last decade, but needs effective collaboration between its government, private sector, neighbours and international donors "so that this decade of transformation can produce results''.
Annual US civilian assistance since 2001 has ranged from $1bn to this year's high of $2.3bn.
Clinton said the aid request to congress through 2017 would be to maintain funding at or near the average level, without specifying further.
Kabul can cover only one-third of the $6bn it spends each year, not counting security costs, and has for a long time been heavily dependent on aid.
But many, both inside and outside the country, fear that once the US and its allies withdraw their troops in 2014, the country could be left to fend for itself.
Roadside bombs, which remain one of the Taliban's weapons of choice along with suicide bombers and commando-style raids, are known to regularly kill civilians.
For the past five years, the number of civilians killed in the war has risen steadily, reaching a record 3,021 in 2011, the vast majority caused by fighters, according to UN figures.
"In these past ten years, with help from the international community, we have made remarkable progress toward healing the scars of conflicts and destruction," Karzai said.
"And we are laying down a new path for people to realise their aspiration of a peaceful and prosperous and democratic country."
According to the World Bank, spending on defence and development by foreign donors accounted for more than 95 per cent of Afghanistan's GDP in 2010-11.
A security conference in Chicago in May, involving the countries of the NATO-led coalition, adopted a plan to provide $4.1bn in annual security aid in coming years. The focus in Tokyo will be on development.
In an interview with the Asahi Shimbun newspaper published on Friday, the Japanese foreign minister, Koichiro Gemba, said he hoped the conference would result in pledges worth at least $3bn a year. But he warned the money would come with strings.
"[Kabul] must improve its governance capacity, including eradicating corruption," he said.
On Saturday, Gemba said donors will stump up more than $16bn for four years to 2015, adding Japan would provide up to $3bn over five years, in addition to $1bn for Afghanistan's neighbours.
"This scale of pledge will satisfy the fiscal gap that the World Bank and the Afghan government have said would be needed for the development of the country," Gemba said.
His announcement came hours after Clinton said the United States had designated Afghanistan a major non-NATO ally, giving it special privileges.
Clinton announced the move, which provides a long-term framework for security and defence cooperation, during a brief visit to Kabul where she had a breakfast meeting with Karzai.