WASHINGTON (CNN) -- Susan Rice, U.S. ambassador to the United Nations, will replace Tom Donilon as President Barack Obama's national security adviser, a senior administration official said Wednesday.
Donilon is resigning, the official said. The president will announce the change Wednesday afternoon at the White House, an administration official said.
Obama will tap Samantha Power, former special assistant to the president and senior director for multilateral affairs and human rights at the National Security Council, as Rice's replacement at the United Nations, a senior administration official also said.
Rice, a longtime Obama confidante, became the center of controversy in the days after the attack on a U.S. diplomatic post in Benghazi, Libya, last year after she maintained the attack was a spontaneous act during a protest rather than the terror attack.
She was considered a top contender to succeed Secretary of State Hillary Clinton at the start of Obama's second term, but Republican pushback forced her to withdraw from consideration in December.
Obama ultimately nominated former U.S. Sen. John Kerry for the post.
Obama picked Donilon -- then deputy national security adviser -- to replace retired Marine Gen. Jim Jones for the post in October 2010. Donilon was heavily involved in the raid to kill Osama bin Laden in 2011.
Rice was considered a possible candidate for the job when Jones stepped down, as she was one of Obama's most public foreign policy voices during his 2008 presidential campaign.
Donilon also served as chief of staff to Secretary of State Warren Christopher in the Clinton administration.
-- CNN's Jim Acosta contributed to this report.
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