US President Barack Obama asked Americans for patience in rebuilding the weak US economy as he appealed for a new term in office last night.

Accepting the presidential nomination at the Democratic National Convention, Mr Obama gave a more down-to-earth follow-up to his 2008 "hope and change" message.

He also rejected Republican Mitt Romney's proposals for growth as heartless.

Mr Obama told Americans they face starkly different paths in choosing between him and Mr Romney in the 6 November election.

He said his way may be hard, but will bring economic renewal, and warned it will take more than the few years he has already had in office to solve challenges that have built up for decades.

"America, I never said this journey would be easy, and I won't promise that now," he said.

"Yes our path is harder, but it leads to a better place. Yes, our road is longer, but we travel it together."

Mr Obama argued that the actions he has taken, such as the bailout of the car industry, are working.

He asked Americans to rally around a set of goals: Expanding manufacturing and energy jobs and US exports, improving education and trimming $4 trillion from America's $16 trillion debt.

"That's what we can do in the next four years, and that's why I'm running for a second term as President of the United States," he said at an arena in Charlotte, North Carolina.

Repeatedly contrasting his own priorities with those he said were Mr Romney's, Mr Obama cast the Republican as not caring for middle-class Americans, pushing a theme that the wealthy Republican is elitist and only interested in helping those like him.

All Mr Romney wants to do, said Mr Obama, is reward the wealthy with tax cuts, deregulate banks and let energy companies write a policy for more oil drilling.

"I don't believe that rolling back regulations on Wall Street will help the small businesswoman expand, or the laid-off construction worker keep his home. We've been there, we've tried that, and we're not going back," he said.

Mr Romney has vowed to cut taxes by 20%, including for the wealthy, and to eliminate some popular income tax deductions to help make up the loss in tax revenues.

He would sharply ramp up oil production and trade with the aim of creating 12m jobs over four years.

Mr Obama tried to pick Mr Romney's proposals apart.

"I refuse to ask middle class families to give up their deductions for owning a home or raising their kids just to pay for another millionaire's tax cut," said Mr Obama.

And he took a shot at Republican vice presidential nominee Paul Ryan's plan to overhaul the Medicare health insurance plan by giving seniors a limited amount of money through vouchers.

"I will never turn Medicare into a voucher. No American should ever have to spend their golden years at the mercy of insurance companies," said the president.

The Romney campaign dismissed Mr Obama's speech as making the case for more of the same policies that have not worked for the past four years.

"Americans will hold President Obama accountable for his record - they know they're not better off and that it's time to change direction," said Mr Romney’s campaign manager Matt Rhoades.

Mr Obama dismissed Mr Romney and Mr Ryan as "new to foreign policy" and criticised a comment Mr Romney made that Russia is America's biggest geopolitical foe.

He mocked Mr Romney for criticising London's handling of the Olympic Games when the Republican visited them in July.

"You don't call Russia our number-one enemy - not al-Qaeda, Russia! - unless you're still stuck in a Cold War mind warp," Mr Obama said.

He compared his struggle to that of Depression-era President Franklin D Roosevelt in calling for "shared responsibility" and bold experimentation in bringing the US economy further out of the worst recession since the Great Depression.

In an attempt to challenge Mr Romney's charge that he is too partial to big government, Mr Obama urged Democrats to "remember that not every problem can be remedied with another government programme or dictate from Washington".

The US economy added 96,000 jobs during August, fewer than the consensus forecast of 125,000. The unemployment rate is 8.2%, which is down 0.2%.

However, the slight fall in the rate was mainly due to a fall in the participation rate, which is the number of people describing themselves as being in the workforce.

Job creation for July was also revised down by 20,000. US equity markets have reacted negatively to the news.