WASHINGTON (AFP) - Michelle Obama urged young Americans not to fear the future but fight for it, delivering an emotive farewell speech Friday (Jan 6) in which she said being First Lady was the greatest honour of her life.

"For all the young people in this room and those who are watching, know that this country belongs to you, to all of you, from every background and walk of life," she said in the East Room of the White House.

After eight years in the White House, Obama will be leaving with her husband on Jan 20, when Donald Trump is sworn in as president.

"Being the first lady has been the greatest honour of my life," she said at an event for School Counsellor of the Year. "I hope I have made you proud."

As First Lady, Obama has played a prominent role in encouraging healthy eating and education for girls and in supporting military families.

But it was as a role model for minorities - as the first African-American First Lady - that she has wielded the most influence.

"If you or your parents are immigrants, know that you are part of a proud American tradition," she told the audience.

"With a lot of hard work and a good education, anything is possible, including becoming president. That's what the American dream is all about," she said.

"Know that religious diversity is a great American tradition too," Obama said. "Our glorious diversity is what makes us who we are."

During the 2016 campaign Obama was a vociferous critic of Trump.

She made no direct reference to the president-elect Friday but the mogul's victory framed much of her remarks.

"You cannot take your freedom for granted," Obama said. "You have to do your part to protect and preserve those freedoms."

"You hear me young people. Don't be afraid, be focused, be determined, be empowered ... lead by example, with hope, never fear."