The Trump administration’s ambassador to the United Nations, Nikki Haley, announced her resignation on Tuesday, telling reporters “there’s no personal reason” for her departure, declining to say what she will move on to next.

Speaking next to US President Donald Trump in the Oval Office, Haley praised him as well as accomplishments made during her tenure, including progress on the issue of North Korean denuclearization. Trump returned her compliments, saying that she was “very special” and would be welcomed back into the administration in whatever role she would like.

He added that Haley had given him warning six months ago that she wanted to take a break.

The timing of her stepping down just several weeks ahead of contentious midterm elections reportedly caught some administration officials off guard, especially considering that she will not be leaving until the end of the year.

The announcement that the highest-ranking female member of Trump’s cabinet will leave also comes one day after the White House ceremony to swear in Supreme Court Justice Brett Kavanaugh. Kavanaugh’s appointment galvanized opposition to the Trump administration among some women’s groups.

While there is no indication that Haley is critical of Kavanaugh’s placement on the court, the context adds questions as to why the administration would choose Tuesday to publicize her resignation.

Haley, who previously served in the US Senate and as governor of South Carolina, pledged to campaign for Trump and indicated she would not be running for office in the near term.

The ambassador has been mostly supportive of Trump, leading the charge to further the administration’s hawkish foreign-policy agenda, but has at times spoken out against the president.

After an anonymous op-ed published by The New York Times, which was attributed to a “senior administration official” who claimed to be part of an internal White House “resistance” to the president, Haley wrote a response opinion piece explaining her approach to criticizing the president.

“I proudly serve in this administration, and I enthusiastically support most of its decisions and the direction it is taking the country. But I don’t agree with the president on everything. When there is disagreement, there is a right way and a wrong way to address it. I pick up the phone and call him or meet with him in person,” she wrote.