Presidential battle on a knife edge
US voters are nearly evenly divided between President Barack Obama and Republican challenger Mitt Romney, with five months to go before the election, polls show.
With unemployment still hovering above 8%, both candidates have stepped up their emphasis on jobs and the economy.
Mr Obama and Mr Romney have offered a starkly differing vision of how the economy should work as they appeal to voters who say jobs are the foremost issue in the November election.
A new Washington Post-ABC News poll shows the pair locked in a dead heat over handling the economy. They are tied at 47%. Overall, 49% said they backed Mr Obama for re-election and 46% preferred Mr Romney, a statistically insignificant difference.
Other recent national polls show a similarly close margin.
Earlier polls generally showed the former Massachusetts governor holding a slight lead over Mr Obama on economic issues and Mr Obama slightly ahead overall.
But the tightening follows an aggressive attack on Mr Romney's business credentials by the Obama campaign, including ads painting him as a job-destroying corporate raider at Bain Capital, the private-equity firm he co-founded.
The Obama campaign has focused on two companies that were closed down or failed after they were absorbed into the web of enterprises under Bain Capital. Mr Romney maintains financial ties to the company but left it years ago to run the Salt Lake City Olympic games and then to serve as Massachusetts governor.
Mr Romney called the attacks "character assassination" but Mr Obama defended the tactic on Monday as legitimate and suggested Mr Romney's background was a poor qualification for the White House since being president involved more than "maximising profits".
The survey found that 80% of Americans still hold a negative view of the economy, but 54% said they felt more positively about the economic situation in the coming years, and 58% felt the financial prospects would improve.