Michelle Obama says she won't run for president

US first lady Michelle Obama has said she had no intention to run for president and plenty of plans to affect change once she leaves the White House next January.

Obama made the remarks at the South by Southwest music festival in Austin, Texas, where she released a single, along with singers Kelly Clarkson, Janelle Monae and former "Glee" star Lea Michele, in support of her worldwide girls' education initiative.

"There are so many ways to impact the world. You don't have to be president of the United States to do wonderful, marvelous things," Obama said at a panel discussion on empowering women at the festival, known as SXSW.

"I will not run for president," Obama, 52, said when asked about her post-White House plans.

Obama, who launched the Let Girls Learn initiative in March 2015, noted at the panel discussion that there are 62 million girls worldwide of school age who are not in school, many of whom are being denied an education and have seen their aspirations snuffed out by grown men.

"For me, 62 million girls not getting an education, that is personal," she said.

The new single, "This is for My Girls," was performed live at SXSW, a festival of music, film and tech in the Texas capital. Proceeds from the single, which also involves singer Kelly Rowland, rapper Missy Elliott and Disney Channel star Zendaya, will go toward the Let Girls Learn initiative.

Obama also had a brief musical interlude at the session, singing a line from the Motown song "It's So Hard to Say Goodbye to Yesterday."

Obama said the platform of first lady was so vast and powerful that she wanted to make sure she did not waste it. Once she leaves the White House, the first lady, who is a lawyer, said she will work in an unbiased way and work to keep reaching people.

"There is so much that I can do outside of the White House and sometimes there is much more that you can do outside of the White House without the constraints," she said.