Hillary Clinton has told voters the presidential election is a “moment of reckoning”, as she made history by accepting the Democratic nomination.
Speaking on the final night of the party’s convention in Philadelphia, the first woman nominated by a major party said there were huge challenges.
“Powerful forces are threatening to pull us apart,” she said.
Mrs Clinton accused her Republican opponent in November’s election, Donald Trump, of sowing discord.
But Mr Trump tweeted that the speech had failed to address the threat posed by radical Islam, making the former secretary of state unfit to lead the country.
Before taking the stage, Mrs Clinton’s daughter Chelsea shared personal memories of her mother.
“My wonderful, thoughtful, hilarious mother,” the 36-year-old said, adding: “She was always there for me.”
After embracing her daughter, the former secretary of state delivered a speech which featured a stark admission about the threats to national unity.
“Bonds of trust and respect are fraying. And just as with our founders there are no guarantees. It’s truly is up to us. We have to decide whether we’re going to work together so we can all rise together.”
She added: “We are not afraid. We will rise to the challenge, just as we always have.”
The risk to American prosperity included inequality, limited social mobility, political gridlock, “threats at home and abroad” and frustration over wage stagnation, she said.
However, she was confident these challenges could be overcome with the American values of “freedom and equality, justice and opportunity”.
She acknowledged that too many Americans had been “left behind” by economic forces and addressed them directly: “Some of you are frustrated – even furious. And you know what? You’re right.”
Another highlight at the convention on Thursday was when the father of a fallen Muslim soldier challenged Donald Trump over his Muslim ban, prompting an ovation.
And General John Allen, former commander of US forces in Afghanistan, appeared on stage with other military veterans and gave Mrs Clinton a ringing endorsement as commander-in-chief.
Mrs Clinton’s high-stakes remarks on the closing night of the four-day convention followed a rousing speech by US President Barack Obama.
He said on Wednesday there had never been a man or woman more qualified than Mrs Clinton to serve as president.
Mrs Clinton and Mr Trump are set for an election battle widely considered to be a tight race when voters head to the polls in November.