Secretary of State John Kerry is seeking to broker a deal between Afghanistan's rival presidential candidates as a bitter dispute over last month's runoff election risked spiraling out of control.

Kerry, who arrived predawn in Kabul on a hastily arranged visit, is meeting Friday with former Finance Minister Ashraf Ghani Ahmadzai (ahsh-RAHF' gah-NEE' ah-mahd-ZEYE') and former Foreign Minister Abdullah Abdullah as well as the current leader, President Hamid Karzai (HAH'-mihd KAHR'-zeye).

The objective is to convince both candidates to hold off on declaring victory or trying to set up a government until the United Nations can conduct an audit of extensive fraud allegations in the voting.

For the United States, the political crisis is threatening to undermine more than a decade of efforts to leave behind a strong Afghanistan.