WASHINGTON (AFP) - An anti-corruption group had urged an investigation into Nikki Haley's acceptance of private aeroplanes and free basketball tickets a day before she resigned on Tuesday (Oct 9) as US ambassador to the United Nations.
Citizens for Responsibility and Ethics in Washington had urged the State Department's inspector-general to probe seven flights that Ms Haley and her husband took last year on the luxury aircraft of businessmen from South Carolina, where she was formerly governor.
Ms Haley, on a filing required of government employees, disclosed the flights from New York to South Carolina and Washington, and estimated the highest value at US$1,066 (S$1,470), based on the cost of commercial first-class tickets.
But the pressure group said that the value was more likely in the tens of thousands of dollars.
It said in its letter that Ms Haley's disclosure form was "insufficient to resolve concerns about her frequent acceptance of expensive gifts".
Mr Walter Shaub, who headed the Office of Government Ethics under president Barack Obama, tweeted about the flights hours before Ms Haley announced her resignation: "She undervalued them and it's not entirely clear if individuals or their companies bore the costs."
Ms Haley also acknowledged receiving four tickets to a New York Knicks game worth a total of US$19,588 courtesy of Mr Vivek Garipalli, a health care entrepreneur she described in the disclosure form as a longtime friend.
Citizens for Responsibility and Ethics in Washington said that the flights could have value in the range of the tickets.
There was no immediate reaction from Ms Haley or indication that the study was connected to her resignation.
Ms Haley, meeting President Donald Trump, said that she wanted time off after six years as governor and nearly two representing his foreign policy at the United Nations.