Long-time Trump adviser Kellyanne Conway steps down

"This is completely my choice and my voice," Xinhua news agency quoted Conway as saying in her announcement on Sunday.

"In time, I will announce future plans. For now, and for my beloved children, it will be less drama, more mama."

Conway, 53, was Trump's campaign manager in 2016.

She has served in her White House role since the beginning of the administration and has been known as a fierce Trump defender.

Also on Sunday, Conway's husband, George, an outspoken critic of the President, tweeted separately that he would be leaving his role with the Lincoln Project, a group of anti-Trump Republicans, for similar reasons.

"We disagree about plenty but we are united on what matters most: the kids," Kellyanne said.

In the announcement, Conway called her time in the White House "heady" and "humbling".

She thanked the President, First Lady Melania Trump, Vice President Mike Pence and Second lady Karen Pence, and offered praise for their work during the administration's first term.

She is expected to speak at the 2020 Republican National Convention this week.

Conway defended Trump through some of his most controversial and difficult moments, The Hill news website said in a report.

Shortly after Trump's inauguration, Conway defended then-press secretary Sean Spicer's inaccurate declaration about the crowd size by saying he was providing "alternative facts".

She was also one of the most egregious violators of the Hatch Act, which prohibits executive branch officials from using their official positions for campaigning.