U.S. President Donald Trump has said Nikki Haley will be leaving her post as UN ambassador at the end of the year.
At a meeting with Haley in the Oval Office at the White House on October 9, Trump confirmed that he had accepted her resignation.
No reason for the resignation was immediately given.
Trump called Haley a "very special" person, adding that she told him six months ago that she might want to take some time off.
Trump said that together they "solved a lot of problems" and said he hoped she could come back to the administration in another capacity.
"We're all happy for you in one way, but we hate to lose (you). ... Hopefully, you'll be coming back at some point. Maybe a different capacity. You can have your pick," Trump said.
Haley said during her meeting with Trump that her job was to defend America on the world stage.
"Look at what has happened in two years with the United States on foreign policy. Now, the United States is respected," she said. "Countries may not like what we do, but they respect what we do."
Haley has promoted a hawkish line on Iran and justified U.S. reductions in foreign-assistance funds.
Also during her term at the UN, the United States earlier this year left the UN Human Rights Council, accusing it of bias against Washington and Israel.
Haley, 46, a former governor of South Carolina, is the daughter of Indian immigrants. She is seen as a rising star in the Republican Party and a possible candidate for the 2020 presidential election.
Despite the speculation, Haley said during the meeting with Trump: "No, I'm not running in 2020."
Haley's departure comes just weeks before next month's midterm elections.
Her departure is the latest in a long list of senior staff members to leave the Trump administration, including former Secretary of State Rex Tillerson, who was fired in March.
Haley, a novice in international politics, became UN envoy in January 2017.
Last month, she coordinated Trump's second appearance at the United Nations, including his first time chairing the Security Council.
Trump said he was considering many candidates for Haley's job and that a successor would be named in two to three weeks.