U.S. ambassador to the United Nations Susan Rice speaks to reporters after a Security Council consultation on the situation in Iran, New York, May 18, 2010.

U.S. Secretary of State Hillary Clinton, left, and U.S. Ambassador to United Nations Susan Rice listen as President Barack Obama addresses the 67th session of the United Nations General Assembly, September 25, 2012.

U.S. ambassador to the United Nations Susan Rice visits a cholera treatment center in Tabarre, outside Port-au-Prince, Haiti, February 16, 2012.

U.S. Ambassador to the United Nations Susan Rice, and British Ambassador Mark Lyall Grant,vote to support a resolution backing an Arab League call for Syrian President Bashar Assad to step down, New York, February 4, 2012.

U.S. ambassador to the United Nations Susan Rice, center, visits residents at the Mandela camp for displaced southern Sudanese, south of Khartoum, in Sudan, May 22, 2011.

President Barack Obama gets ready to take his seat as South Korean President Lee Myung-bak greets U.S. Ambassador to the U.N. Susan Rice, Blue House in Seoul, South Korea, November 19, 2009.

Susan Rice, U.S. ambassador to the United Nations, speaks to students and faculty at the Howard University School of Law in Washington, October 8, 2009.