Nato members are considering sending more troops, more quickly to help secure Afghanistan's upcoming elections - on top of what the alliance just agreed to at its summit in Istanbul.
"We're going to try to do more," a senior Bush administration official told reporters, adding that the United States wants the deployments "the earlier the better" to provide security in the run-up to the September vote.
The official said the discussions got under way on the sidelines of the Nato summit, where President George W. Bush met yesterday with Afghan President Hamid Karzai.
He declined to discuss the number of troops that might be involved.
The negotiations follow Mr Karzai's personal appeal to Nato leaders in Istanbul to "hurry" with extra troop deployments before voters go to the polls.
Nato currently has a force of 6,500 troops in Afghanistan.
The alliance decided on Monday to deploy roughly 1,500 extra military personnel in Kabul and the relatively stable North of the country during the elections, and a further 700 to take command of four "reconstruction teams" in the North.
But the figures fall far short of the 5,000 the United Nations and the government want to secure the elections, which Taliban militants have vowed to disrupt.
For now, the additional Nato forces agreed in Istanbul are not expected to arrive in the country until closer to the elections because allied nations have been slow to offer troops and crucial but costly equipment such as helicopters and transport planes for the mission.
"I welcome very much your decision yesterday to send us security forces to help us with the elections," Mr Karzai told Nato leaders in Istanbul.