US President Donald Trump is set to announce state department spokeswoman Heather Nauert as his new ambassador to the United Nations, US media report.
One of the reports came from Fox News, where Ms Nauert has previously worked as a presenter.
Nikki Haley had announced in October that she was leaving the post by the end of the year.
Ms Nauert, 48, was made state department spokeswoman in April 2017, her first government position.
The state department has made no comment.
Bloomberg said Ms Nauert would be an unorthodox choice, given the little experience she had in government or foreign policy before she took up the role at the state department.
In addition to that role, Ms Nauert was appointed acting undersecretary for public diplomacy and public affairs in March this year.
Her appointment to the UN role would have to be approved by the US Senate.
Ms Nauert worked for Fox News from 1998 to 2005 and, after two years away during which she worked for ABC, she returned to Fox in 2007, later becoming a presenter for Fox & Friends.
Fox News has been a consistent supporter of the president and he often cites its news.
Ms Haley has served nearly two years in the post.