WASHINGTON • An anti-corruption group had urged an investigation into Ms Nikki Haley's acceptance of private airplanes and free basketball tickets a day before she resigned 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$1,471), 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 on Tuesday: "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 Vivek Garipalli, a healthcare entrepreneur she described in the disclosure form as a long-time friend. Citizens for Responsibility and Ethics in Washington said 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.