Former American Secretary of State Hillary Clinton formally declared her presidential bid.

Former American Secretary of State Hillary Clinton formally declared her presidential bid, US media outlets reported Sunday.

"I'm running for president," she said at the end of a video message posted to her new campaign website.

Clinton ran for Democratic nomination in 2008 but eventually lost to President Barack Obama.

"Everyday Americans need a champion. I want to be that champion" she said in the two-minute video, entitled Getting Ready. "So I am hitting the road to earn your vote - because it is your time. And I hope you will join me on this journey."

US news analysts consider Clinton the strongest contender for the party's 2016 presidential race announced so far.

Winning the White House would make her the first female US president in history.

The public announcement came minutes after an e-mail message declaring the candidacy was sent to donors, supporters and elected officials, the New York Times said.

On the eve of the expected announcement, President Obama said Clinton would make an "excellent president."

"She was a formidable candidate in 2008. She was a great supporter of mine in the general election," Obama told reporters in Panama on Saturday. "She was an outstanding secretary of state. She is my friend. I think she would be an excellent president."

During her campaign, she is expected to hold small discussion events with voters instead of large rallies and extended announcement speeches like that of some of her Republican rivals.

Two Republicans, Ted Cruz and Rand Paul, have formally announced their bids.

Clinton served as a politically active first lady during the 1993-2001 administration of her husband, Bill Clinton, and as secretary of state in Obama’s administration from 2009 to 2013.

She recently faced broad criticism when it was revealed she conducted official business on a personal e-mail account despite an administration-wide policy forbidding such use.