The United States has paid Pakistan $256m for Islamabad's support in military operations in Afghanistan, the Pakistan Central Bank says.
Correspondents say the payment is reward for the use of Pakistan's military bases during US operations against the former Taleban government.
Last month, President Bush promised to give Pakistan $3bn in economic and military aid over the next five years, although the proposal still needs the approval of the US Congress.
The exact role the bases played in the war was never fully disclosed, but Pakistani President Pervez Musharraf says no combat operations were launched from Pakistan.
From the newsroom of the BBC World Service