US President Donald Trump's top economic adviser Gary Cohn is resigning, the White House has said.
It is the latest in a series of high-profile departures from President Trump's team.
There has been speculation that Gary Cohn, a supporter of free trade, was angered by Mr. Trump's plans to impose tariffs on aluminium and steel imports.
In a statement released by the White House, Mr. Cohn said it had been "an honour to serve my country".
The 57-year-old former president of the Goldman Sachs bank helped Mr. Trump push through his sweeping tax reforms late last year.
However, Gary Cohn and President Trump were never believed to be close.
In August 2017, Mr. Cohn criticised Mr. Trump over his reaction to a far-right rally in Charlottesville, Virginia, saying the administration "can and must do better". He was reported to have drafted a resignation letter after the event.
"It has been an honour to serve my country and enact pro-growth economic policies to benefit the American people, in particular, the passage of historic tax reform," Mr. Cohn said in his statement.
"I am grateful to the president for giving me this opportunity and wish him and the administration great success in the future."
Gary Cohn had reportedly set up a meeting between Mr. Trump and business executives who opposed the tariffs move. But Mr. Trump pulled out of that meeting and on Tuesday reportedly asked Mr. Cohn in the Oval Office to back the tariffs publicly. Mr. Cohn did not answer, sources told Bloomberg.
In August last year, Mr. Cohn had also criticised Mr. Trump over his reaction to a far-right rally in Charlottesville, Virginia, saying the administration "can and must do better". He was reported to have drafted a resignation letter after the event.