Nikki Haley, the United States’ ambassador to the United Nations, resigned from her post on Tuesday, The New York Times reported. She gave no reason for her exit, but President Donald Trump said she had told him six months ago she wanted to take some time off.

After accepting her resignation, President Donald Trump told reporters that she would be leaving the post at the end of the year after doing “an incredible job”. He said he hoped Haley would return in a different role. He said he would name her successor in the next two to three weeks.

Haley had served in the position since January 2017. She said she was not planning to run for president in 2020 and would campaign for Trump instead.

“I think you have to be selfless enough to know when you step aside and allow someone else to do the job,” she said.

Haley is the latest among several top officials in President Donald Trump’s administration who have quit since he came to power to 2016. She is a former South Carolina governor, and a daughter of Indian immigrants.

Haley has made statements that have appeared to be critical of Trump on several occasions. In December 2017, she said that women who had accused Trump of sexual misconduct “should be heard”.

Other resignations and sackings in the Trump administration have included those of Health and Human Services Secretary Tom Price, Secretary of State Rex Tillerson and Veteran Affairs Secretary David Shulkin. In July, Scott Pruitt resigned as chief of United States Environmental Protection Agency.

Others who have either resigned or been sacked in recent months include Chief Economic Adviser Gary Cohn and National Security Adviser HR McMaster. National Security Adviser Michael Flynn resigned in February 2017, White House Chief of Staff Reince Priebus in July 2017, and Chief Strategist Steve Bannon in August 2017.