The United States is planning to boost its spending in Afghanistan and says it is bolstering its military commitment to the country.
The US says its Nato allies must do more for Afghanistan
Secretary of State Condoleezza Rice said President Bush would ask Congress for an extra $10.6bn to fund security and development in Afghanistan.
Ms Rice made the announcement on the eve of a Nato meeting on Afghanistan in Brussels, which she is due to attend.
Earlier the Pentagon said thousands of US forces would stay on in Afghanistan.
It said 3,200 men of the 3rd Brigade, 10th Mountain Division would remain in the country for an extra four months after their tour of duty is meant to end.
It comes amid expectations that the Taleban will try to mount a spring offensive.
The BBC's Rob Watson in Brussels says this latest push by Washington is motivated in part by a desire to show its Nato allies it is not abandoning Afghanistan despite its troubles in Iraq.
But, he adds, the US is also genuinely worried that Afghanistan could slip backwards without more commitment from the international community.
On her way to Brussels, Ms Rice told reporters $8.6bn of the extra money would be spent on security, including training and equipping Afghan forces, while $2bn would go towards reconstruction.
The money would be spent over the next two years.
At the Brussels summit, Ms Rice will also press other Nato nations to do more in Afghanistan.
Our correspondent says the hastily arranged meeting of Nato foreign ministers was called for by Ms Rice to press the point home.
"The challenges of the last several months have demonstrated that we want to, and we should, redouble our efforts" in Afghanistan, she said.
The US has already committed some $14.2bn in aid to Afghanistan since the 2001 invasion which toppled the ruling Taleban regime.
The aid plan for Afghanistan was unveiled as the US stepped up its military commitment to the country.
The Pentagon said keeping the troops on would enable Nato to "maintain the initiative and build upon the success achieved in promoting stability and security".
It comes only days after the Nato commander in Afghanistan, Gen David Richards, told a British newspaper he had "less troops than needed" to complete his task.
There are currently 24,000 US troops in the country, which make up the bulk of the foreign military presence.
Nato commanders have said their forces were around 10% under strength due to some nations failing to make good on pledges to provide more troops.
Just under half the US force are part of the 31,000-strong Nato peacekeeping command - the rest are on a separate mission to hunt down al-Qaeda fighters.