President Trump left Turnberry on Sunday after spending four days in the UK.
The US secret service has confirmed one of its agents died after suffering a stroke during Donald Trump's visit to his Turnberry golf resort. "President Trump not only used the occasion of a state visit to promote his Trump-branded golf course, but told USA taxpayers to foot the bill", said Brendan Fischer, director of federal reform for Campaign Legal Center.
It was not clear whether all of the payments were made to cover expenses for Trump's visit.
The Trump Organization and the White House did not immediately respond to requests for comment from Business Insider.
"This is part of a pattern with this president of really doing everything he can to disgrace the office of the presidency by promoting his own private business interests", said Stephen Spaulding, a lawyer with the public interest group Common Cause.
While other recent presidents have put their assets in a blind trust, Trump has retained ownership of his hotels, golf courses and other businesses. He handed control of the businesses to his sons shortly before he took office in January 2017.
No further details have been released, including his name, as the service seeks to give his family privacy and time to inform others of his death. Its directors include Eric Trump and Donald Trump Jr.
The Trump Organization told The Washington Post this week that Trump-owned properties do not profit from USA government business.
"For United States government patronage, our hotels charge room rates only at cost and we do not profit from these stays", said the statement, attributed to George Sorial, the company's chief compliance counsel.
The US taxpayers' money went towards hotel rooms used by Mr Trump and his staff during his two night stay at Turnberry, which the president said would be dominated by meetings and calls.