Secretary-General Ban Ki-moon fired the top American official at the U.N. mission in Afghanistan on Wednesday after a widely publicized dispute with his boss over how to deal with widespread fraud charges in the country's presidential election.

U.N. spokeswoman Michele Montas said in a statement that Ban decided to recall Peter Galbraith and end his appointment as the U.N.'s deputy special representative.

Diplomats said Galbraith disagreed with the head of the U.N. mission, Kai Eide, over how the U.N. should handle the disputed election.

The secretary-general reaffirmed "his full support for Eide" and made his decision "in the best interest of the mission," Montas said.

Neither Galbraith nor Eide, a Norwegian diplomat, have offered details of the disagreement, though Eide has confirmed that the two split over election issues.

The delay in final results from the Aug. 20 vote has led to fears of a power vacuum in the Afghan government that could endure until spring, even as Taliban violence against U.S. and NATO soldiers and Afghan civilians continues to rise.

The U.N. Mission in Afghanistan, known as UNAMA, had a mandate to support the Afghan government in conducting the Aug. 20 elections. It also has a mandate to lead international civilian efforts to provide aid, promote reconstruction, combat corruption, help improve civilian-military cooperation, and expand the U.N. presence throughout the country to promote good governance and the rule of law.

Britain's U.N. Ambassador John Sawers said: "We believe Peter Galbraith brought energy and ideas, but there has to be a single leadership on the main issues of policy."

Sawers said Galbraith and Eide had a policy dispute on UNAMA's post-election role.

"I think it's mainly a question of whether it was the U.N.'s role to determine the validity or otherwise of the election and the results of that election," he said.

"In fact, Mr. Eide is correct in saying that those responsibilities rest with other bodies — the Independent Election Commission and the Election Complaints Commission. They are independent bodies," Sawers said.

Galbraith oversaw electoral matters for the U.N. before and after the vote. Following allegations of widespread vote-rigging, he reportedly pressed the Election Commission to conduct a wide-ranging recount.

Eide has been criticized for initially praising the election — before the full extent of the fraud became known — and saying it represented "an important achievement" for the people of Afghanistan.

Asked about Galbraith's departure, U.S. Secretary of State Hillary Clinton, who chaired a meeting of the U.N. Security Council on Wednesday, told reporters: "That's a United Nations matter."

Just a day ago on Tuesday, the secretary-general responded to a question about whether Galbraith would keep his job and return to Afghanistan.

"He is still as deputy special representative of UNAMA," Ban replied.

Pressed on whether he would remain deputy special representative, the secretary-general said, "I think I don't need to answer for that question for anything which may happen in the future. We will have to assess the situation."

In an e-mail to the British Broadcasting Corp., which first reported he had lost his job, Galbraith said: "The secretary-general appointed me and has not fired me so far as I know."

Galbraith has been in the United States since mid-September, when he left Afghanistan. A call to his home in Vermont seeking comment was not immediately returned.

Galbraith worked for the U.N. in East Timor in 2000-2001 and as the U.S. ambassador to Croatia from 1993 to 1998. He is close to Richard Holbrooke, the U.S. special envoy to Afghanistan and Pakistan, and became friends with Eide in the Balkans.

Ban thanked Galbraith "for his hard work and professional dedication" and recognized his "important contributions to the work of the mission and throughout his distinguished career as an international civil servant," Montas said.