President Barack Obama plans to appoint U.S. Ambassador to the United Nations Susan Rice as his national security adviser, replacing Tom Donilon, who is resigning, a White House official said on Wednesday, in a major change in his foreign policy team.
Obama plans to make the appointment, first reported by the New York Times, later on Wednesday.
He also will nominate Samantha Power - a Pulitzer Prize-winning author, former White House aide and Harvard professor - as U.N. ambassador, the White House official said.
Rice's appointment as Obama's top security adviser does not require Senate confirmation.
Obama had wanted to name Rice as his secretary of state, but she ran into heavy opposition from Republicans over remarks she made in the aftermath of the September 11, 2012, attack on the U.S. mission in Benghazi, Libya, that killed four Americans, including Ambassador Christopher Stevens.
Rice, a close confidante of Obama, withdrew her name from consideration for the top diplomatic post in December.
Donilon, who served for more than four years as Obama's top national security adviser, will leave in early July, a White House official said.
The shake-up comes as the Obama administration struggles with its response to the civil war in Syria.