President Obama will appoint United Nations ambassador Susan Rice as his new national security adviser, replacing Tom Donilon, officials said Wednesday.

Obama had considered Rice for Secretary of State late last year, but appointed John Kerry instead in part because of controversy surrounding the Sept. 11 attack in Benghazi, Libya

White House officials confirmed the appointment on the condition she not be named, so as not to preempt Obama's formal announcement later Wednesday.

Senate Republicans had threatened to block Rice's nomination to the State Department -- but the Senate has no say in the national security adviser's job.

The job switch comes as Obama prepares for a summit with Chinese President Xi Jinping; Donilon was in Beijing recently preparing for the meeting.

Donilon's retirement has been expected sometime this year, and Rice has long been considered the top candidate for his replacement.