WASHINGTON - The top Republican on the Senate Foreign Relations Committee says he's holding up $75 million in U.S. assistance to Afghanistan until he gets answers from the Obama administration about alleged cash payments from the CIA to Afghan President Hamid Karzai.

Sen. Bob Corker says in a letter sent Monday to Secretary of State John Kerry and Rajiv Shah, administrator of the U.S. Agency for International Development, that he has made repeated requests for information about the alleged payments.

But he has received no response.

Corker says such payments illustrate an inconsistency in U.S. policy that seeks to root out corruption in Afghanistan while at the same time allegedly funneling cash to the country's president.

The senator says the $75 million is intended to be used for electoral programs in Afghanistan.