Washington (CNN) President Donald Trump has mentioned former Michigan GOP Senate candidate John James as a leading contender for the role of US ambassador to the United Nations, a source close to White House tells CNN.

State Department spokeswoman Heather Nauert announced Saturday she had withdrawn from consideration as UN ambassador, keeping the position open.

The State Department said Saturday that Trump will make an announcement about a new nominee soon.

Trump, who sounded out the idea of selecting James with trusted advisers around Mar-a-Lago over the weekend, is "very impressed by him ... and sees him as a rising star," the source said. James lost the Senate bid in November to Democratic Sen. Debbie Stabenow.

James, a veteran of the Iraq War, had previously interviewed with Trump for a role in the administration and was seen as a top prospect for the UN job when the position was offered to Nauert. Trump sees the UN job as a "PR position," which is why Nauert, a former Fox News reporter, was selected the last time around, the source said.

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