US president Barack Obama arrived in Charlotte, North Carolina, for the Democratic National Convention, where a possibility of severe weather prompted the campaign to scrap plans for his outdoor speech in a football stadium.
Democratic officials today moved Mr Obama's nomination acceptance speech tomorrow night from the almost 74,000-seat Bank of America Stadium to the Time Warner Cable Arena, where the convention began yesterday.
"This isn't a call we wanted to make," campaign spokesman Jen Psaki told reporters travelling with the president to Charlotte. "We're all disappointed."
First lady Michelle Obama will introduce her husband before he makes his speech, according to a Democratic official involved in the convention's operation. The Time Warner arena holds about 20,000 people.
Those who had credentials to attend the outdoor event and won't have seats for the indoor speech are invited to be part of an Obama conference call tomorrow, the party officials said.
Democratic officials said they had a 19,000-person waiting list and weren't worried about filling the outdoor arena. Moving the speech to the smaller venue hurts efforts to organise and register voters, they said.
Michelle Obama last night used an opening-night convention speech to take Americans inside the White House, asking them for the patience to give her husband a second term and contrasting Obama's life experience with Republican challenger Mitt Romney's.
Nancy Pelosi, a California Democrat, said moving Mr Obama's speech indoors will not take away from his message.
"Whether it rains or not is not in the president's control," Ms Pelosi told reporters today at a Christian Science Monitor breakfast in Charlotte. The decision to move the speech was made "to ensure the safety and security of our delegates and convention guests," Steve Kerrigan, chief executive officer of the DNCC, said in a statement.
The US National Weather Service is forecasting a 40 per cent chance of thunderstorms for tomorrow in the Charlotte area, where it has rained much of the week.
Weather also disrupted the Republican National Convention last week in Tampa, Florida, with Hurricane Isaac causing officials to cancel the opening day of the gathering.
Former president Bill Clinton headlines tonight's convention speakers, and he will present "a clear difference" in the economic visions of Mr Obama and Mr Romney, campaign manager Jim Messina told reporters.
Mr Clinton will talk about the choices he faced 20 years ago when Republicans wanted to give tax breaks to companies and the wealthy "to help trickle down" economic benefits and how
"it didn't work then, it's not going to work now," Mr Messina said.
"President Clinton did what president Obama wants to do, which is invest in education, invest in innovation, invest in infrastructure to create an economy built to last," he added.
"We did that under president Clinton, it created the best job growth of a generation, and that's what we're building."
Mr Clinton will be competing for viewers with a prime-time broadcast on NBC of the National Football League's opening game between the New York Giants and the Dallas Cowboys.
Tonight's speakers also include Elizabeth Warren, who is challenging Republican Scott Brown for his Senate seat in Massachusetts. Ms Warren, a Harvard Law professor who helped set up the federal Consumer Financial Protection Bureau under Mr Obama, is her party's hope to recapture the seat long held by Ted Kennedy, who died in office in 2009.
She'll highlight what Romney's plan to roll-back Wall Street regulations would mean for consumers. Former employees of companies bought by Mr Romney's private-equity firm Bain Capital LLC will also address delegates, officials said.
Mr Obama and allied political action committees have attacked Mr Romney over his work at Bain, linking him to job layoffs and outsourcing by companies that the firm invested in.
Mr Romney, who is taking a break from campaigning this week to huddle with top advisers on a Vermont estate preparing for next month's presidential debates, came out of seclusion briefly to travel to a building supply store in nearby West Lebanon, New Hampshire and to sit for several television interviews.
He also spoke briefly to reporters and criticised Mr Obama's fiscal record, saying Democrats during their convention's first day avoided talking about the US debt that has ballooned and poverty that has deepened during Mr Obama's presidency.
"You heard no one stand up and say that people are better off today than they were four years ago," Mr Romney said after stopping at the Lui Lui restaurant to pick up pizza. "They really can't say that."
He said news this week that the national debt has reached $16 trillion - up from $10 trillion when Mr Obama became president - and that the number of food-stamp recipients has reached 47 million tell the story of Mr Obama's failed record.
"There's just no way he can square those numbers with the idea that America is doing better, because it's not," Mr Romney said.
Bloomberg