"We stand against those who exploit their positions of power and influence to deprive the Afghan people of the benefits of foreign assistance and a more prosperous future," Secretary of State Mike Pompeo said in a statement.
Pompeo said that the United States was suspending work with the Afghan body in charge of monitoring corruption as it is "incapable of being a partner."
"We expect the Afghan government to demonstrate a clear commitment to fight corruption, to serve the Afghan people and to maintain their trust," he said.
"Afghan leaders who fail to meet this standard should be held accountable."
Pompeo said the United States was taking back $100 million committed for a major energy project, saying that Washington would fund it directly rather than sending the money through Afghan authorities.
He also said the United States would withhold $60 million in planned assistance to Afghanistan's procurement authority. Ghani stands for re-election on September 28 in the campaign already marred by Taliban violence, with dozens killed this week including in an attack on a Ghani rally.
The last election, in 2014, ended in allegations of rigging and a political stalemate between Ghani and Abdullah Abdullah, who is again running. They eventually reached a power-sharing arrangement after brokering by then US secretary of state John Kerry.
Pompeo, speaking to reporters in Abu Dhabi, said that the United States wanted "free and fair elections," adding: "We're going to do everything we can to support them."