U.S. Deputy Secretary of State William Burns, whose back-channel talks with Iran are credited for jumpstarting negotiations over the country's nuclear program, announced he is retiring in October of 2014.
Reacting to his retirement, President Obama said Burns' service made this country stronger.
"Since I took office, I have relied on him for candid advice and sensitive diplomatic missions," President Obama said in a statement. "He has been a skilled advisor, consummate diplomat, and inspiration to generations of public servants.
"[Secretary of State John] Kerry compared him to George F. Kennan and Charles E. Bohlen, and said he "has more than earned his place on a very short list of American diplomatic legends."
"Mr. Burns's decision to delay his departure until October raises the possibility that he may again play a role on Iran policy should formal negotiations fail to produce a comprehensive agreement to restrict Iran's nuclear program by their July deadline.
"A successor for Mr. Burns has yet to be chosen. But the candidates are likely to include Antony Blinken, Mr. Obama's deputy national security adviser, and Wendy R. Sherman, the under secretary of state who is leading the American team in the formal nuclear negotiations with Iran."
Reuters reports that Burns was the top U.S. diplomat for the Middle East and had served as ambassador to Russia.