Michelle Obama angrily attacks 'disgraceful' Donald Trump

She lashed out at what she called Trump's 'cruel' and 'frightening' attitude towards women, without using his name

US First Lady Michelle Obama today launched a scathing takedown of Republican presidential nominee Donald Trump, calling his sexually aggressive comments about women "disgraceful" and "intolerable."

Obama, a Harvard-educated lawyer who has largely shunned the political limelight to focus on education and health issues, galvanized a rally for Democrat Hillary Clinton in New Hampshire with an impassioned plea to "stop this madness."

Her comments came as Trump fought back against a cascade of allegations of sexual misconduct, which surfaced just days after a video emerged of him boasting that his fame allowed him to grope women with impunity.

"This wasn't locker room banter. This was a powerful individual speaking freely and openly about sexually predatory behavior. And actually bragging about kissing and groping women," said the 52-year-old first lady.

"It doesn't matter what party you belong to — Democrat, Republican, independent — no woman deserves to be treated this way. No one deserves this kind of abuse."

She lashed out at what she called Trump's "cruel" and "frightening" attitude towards women, while deliberately never using his name.

"It has shaken me to my core in a way that I couldn't have predicted," she said.

"This is not normal. It is not politics as usual. This is disgraceful. It is intolerable."

Trump's presidential bid was teetering after claims from at least six women surfaced, alleging that he had made unwanted sexual advances towards them in the past, including groping and kissing.

The Manhattan billionaire said on Sunday in his second presidential debate with Clinton that despite his lewd conversation with then "Access Hollywood" host Billy Bush in 2005 captured on video, he had never sexually assaulted women.

Trump has vehemently denied the claims reported by various US media outlets including The New York Times, NBC and People magazine, slamming them as politically-motivated and threatening to sue the Times.

"The phony story in the failing @nytimes is a TOTAL FABRICATION," Trump posted on Twitter. But Michelle Obama nevertheless attacked him with a vengeance.

"The men in my life do not talk about women like this," she said. "This is not how decent human beings behave and this is certainly not how someone who wants to be president of the United States behaves."

She championed Clinton as a unifying force and said only she could help "heal the wounds that divide us."

The first lady warned that if Trump were elected, "we're telling our sons that it's okay to humiliate women. We're telling our daughters that this is how they deserve to be treated."

"While our mothers and grandmothers were often powerless to change their circumstances, today we as women have all the power we need to determine the outcome of this election," Obama said to cheers.

"We have knowledge. We have a choice. We have a vote.