U.S. President Barack Obama and his Republican challenger in the 2012 election Mitt Romney are still deadlocked nationally with voters' support, right ahead of their respective party's national conventions expected to rejuvenate their campaigns, according to a poll released on Monday.

The latest Washington Post-ABC News poll showed that Romney edged Obama 47 percent to 46 percent among registered voters, which was well within the poll's 4-percentage-point margin of error.

As both sides agreed that economy remains a top issue in this year's election, the poll had some bad news for Obama, who continued to get more negative reviews than positive ones for his handling of the economy. However, ratings have not further deteriorated, the poll found.

Romney, who will formally accept the Republican presidential nomination during this week's party convention in Tampa, Florida, beat Obama by seven points among registered voters on handling the economy. Obama led an equivalent advantage over Romney on better understanding the financial problems people are facing.

The Obama campaign's portrait of Romney as a self-serving businessman seemed to work well. The new poll found that nearly six in 10 voters saw Romney as a president who would do more to help the wealthy than the middle class. About six in 10 said Obama would do more to help the middle class.

Just like the findings of a recent Gallup poll, the new poll showed that Obama still won over Romney in likeability by 61 percent to 27 percent. Obama also held a double-digit lead on social issues and women's issues, which sidetracked the campaign in recent weeks.

In this latest poll, Obama's approval rating is 50 percent positive and 46 percent negative among all Americans. However, he has to do more to thrill the base during the Democratic National Convention, to be held next week in North Carolina. In the new poll, his enthusiasm gap has been narrowed following Romney's pick of Paul Ryan as running mate.

Currently, 48 percent of Obama supporters are "very enthusiastic" about his candidacy, while 42 percent of Romney backers feel that way about the Republican campaign. Obama once led by a 13-point edge in July on enthusiasm, and by 25 points in May.

On demographic divisions, 49 percent of female voters support Obama and 43 percent support Romney, while men break 51 percent to 42 percent in favor of Romney. White voters break for Romney by 18 percentage points, while non-whites back Obama by better than three to one.