The announcement marked her return to the political arena following Clinton’s election defeat at the hands of Republican US President Donald Trump in November last year.

“The last few months, I’ve been reflecting, spending time with family-and, yes, taking walks in the woods,” the former Democratic candidate Clinton said in a series of tweets announcing the news.

“More than ever, I believe citizen engagement is vital to our democracy. I’m so inspired by everyone stepping up to organize and lead,” she said.

“This year hasn’t been what I envisioned, but I know what I’m still fighting for: a kinder, big-hearted, inclusive America. Onward!” she continued.

Clinton specifically mentioned five groups that the new movement would support, including Indivisible, whose stated aim is to “resist Trump,” a racial justice organization called Color of Change and a leading Democratic women’s training program, Emerge America.

Run for Something, a group that helps young people run for office, and Swing Left, a campaign to support Democrats to win back the House of Representatives in the country’s 2018 mid-term elections, will also receive support from the Onward Together movement.

“In some cases, we’ll provide direct funding to these organizations,” Clinton emailed to supporters on Monday, according to various US media.

“For others, we’ll help amplify their work and do what we can to help them continue to grow their audiences and expand their reach.”

Following the announcement, Run for Something wrote Monday that they were “incredibly grateful and humbled to have [Hillary Clinton] on our team.”

“We’re going to be able to do even more for our candidates because of Onward Together’s immediate support,” the group said.

According to the Huffington Post, Onward Together is organized as a social welfare non-profit organization under section 501(c)(4) of the US Internal Revenue Code.

That means it can collect contributions from any source without revealing the names of its donors, the website said.