A suicide bomber struck the Afghan Defense Ministry building, killing 10. It is the same facility where Hagel was to meet with his Afghan counterpart ahead of his meeting with Karzai. Hagel is making his first trip to Afghanistan since being confirmed as U.S. secretary of defense.
A dinner between Hagel and Karzai was to go on as planned Sunday.
Officials said the cancellation had nothing to do with comments Karzai made earlier, that the U.S. military was colluding with the Taliban to keep stirring up trouble in order to keep U.S. forces in the country.
The reassurances came after Karzai said in a televised interview the Taliban was acting in concert with the Americans in order to slow down its troop withdrawal in the coming months.
"This is simply incorrect," one unnamed U.S. official told Stars and Stripes. "The United States and the government of Afghanistan share a common view of the Taliban, and that is that they are the enemy."
The official told the U.S. newspaper whatever political settlement is hammered out between Karzai and the Taliban will come from "an Afghan-led process."
Karzai, who has made outlandish statements in the past, said weekend bombings in the cities of Kabul and Khost were proof the Americans and Taliban were maneuvering to stoke fears over Afghanistan's security and keep U.S. combat forces in country beyond 2014. The alleged motivation for such a scenario was unclear.