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.
In a statement released by the White House, Mr Cohn said it had been "an honour to serve my country".
There has been speculation that Mr Cohn, a supporter of free trade, was angered by Mr Trump's plans to impose tariffs on aluminium and steel imports.
Mr Cohn, a former president of the Goldman Sachs bank, helped Mr Trump push through his sweeping reforms on taxes late last year.
However, the two were not believed to be close.
- Trump: EU makes business 'impossible'
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."
Earlier on Tuesday, President Trump tweeted that there was no chaos at the White House but there were "still… some people that I want to change".
Skip Twitter post by @realDonaldTrump
The new Fake News narrative is that there is CHAOS in the White House. Wrong! People will always come & go, and I want strong dialogue before making a final decision. I still have some people that I want to change (always seeking perfection). There is no Chaos, only great Energy!
— Donald J. Trump (@realDonaldTrump) March 6, 2018
End of Twitter post by @realDonaldTrump
Last week, one of Mr Trump's closest aides, Hope Hicks, resigned. She was the fourth person to have served as the president's communications chief.
It came a day after she had testified in front of the House Intelligence Committee investigating possible Trump campaign ties to Russia, but White House sources said this was not the reason.