Kaine said on Thursday that he "humbly" accepted his party's nomination for the vice presidency, adding that he accepted it on behalf of his wife, Anne, "and every strong woman in this country."

The Virginia Senator said he would also do it for his friend, and running mate, the presidential nominee Hillary Clinton.

Kaine claimed the country's other option to be president - Republican Donald Trump - was a "one-man wrecking crew." The nominee said that Trump had asked Americans to believe he'll build a wall with Mexico, and destroy the Islamic State group "so fast."

Kaine asked: "Here's the question: Do you really believe him? Donald Trump's whole career says you better not."

Meanwhile, Kaine added, Hillary Clinton had shown she had the qualifications to lead the country.

"We'd better elect the candidate who's proven she can be trusted with the job ... who's proven she's ready for the job," he said.

'Not really a facts guy'

Speaking after Kaine, President Barack Obama echoed Obama's endorsement of Clinton. "I can say with confidence there has never been a man or a woman more qualified than Hillary Clinton to serve as President of the United States of America," said Obama.

"Hillary has real plans to address the concerns she's heard from you on the campaign trail. She's got specific ideas to invest in new jobs, to help workers share in their company's profits, to help put kids in preschool, and put students through college without taking on a ton of debt. That's what leaders do."

Obama also slammed Trump's vision for America, as set out in his speech at the Republican National Convention in Cleveland the previous week.

"What we heard was a deeply pessimistic vision where we turn against each other and turn against the world." The president lampooned Trump as "not really a plans guy. Not really a facts guy, either."

"Does anyone really believe that a guy who's spent his 70 years on this Earth showing no regard for working people is suddenly going to be your champion? Your voice?"

'Speaking is difficult for me'

Earlier in the evening, former Arizona congresswoman Gabby Giffords - who was nearly killed when she was shot in the head by an assailant in 2011- talked about the need for the Democrats to challenge the US gun lobby. Giffords, who remarkably survived but was left with speech problems, also added her support for Clinton. "Speaking is difficult for me," said Gifford: "But come January, I want to say these two words: Madam President."

Longstanding and outgoing Democrat Senator Harry Reid said the Senate's Republican leader Mitch McConnell had slandered President Barack Obama as the first black US president, stirred up hatred of Latinos and sowed fear of Muslims. The Nevada senator said parents were right to worry about children hearing Trump whip up discord, claiming Trump had learned it from watching the Republicans.

Earlier still, movie director James Cameron called Trump "a madman," saying he was "incredibly reckless, incredibly dangerous" when it came to global warming.

Cameron, the director of "Titanic" and "Avatar" made a short film that aired at the convention about how climate change is harming the US. The film shows wildfires, heat waves and the aftermath of Superstorm Sandy - and then cuts to Trump calling man-made global warming a "hoax."

rc/msh (AP, AFP)