U.S. President Barack Obama and his Republican challenger Mitt Romney are still neck and neck in the 2012 presidential race despite their early campaign advertising blitz, according to a poll released on Tuesday.

The Washington Post-ABC News poll showed that Obama and Romney remain in a deadlocked contest, tied at 47 percent among registered U.S. voters, little changed from the situation in late May.

Only twice in 13 polls in more than a year has either candidate held a lead exceeding the poll's margin of sampling error, which is about 4 percent in the latest one. The race appears destined to remain extremely close in the final four months before the Election Day in November, The Washington Post said in a report.

About two-thirds of Americans consider the country seriously off course, while a majority disapprove of Obama's overall job performance in more than a year. Obama remains in negative territory on dealing with the economy, health care and immigration, it noted.

American voters' attitude has barely changed despite the two campaigns have launched a costly blitz of early advertising. The Obama campaign attacks Romney for outsourcing jobs while serving as head of the investment company Bain Capital, while the Romney camp highlights the poor economic record of the Obama administration in the past three years.

At this point, 74 percent of all voters are "definitely" supporting Obama or Romney, and another 12 percent say it is unlikely that they will switch side, which means nearly nine in 10 voters have made up their mind about the vote.

Such a high level of early commitment among voters shifts the focus to turnout on the Election Day in November -- and to which side can muster the most effective get-out-the-vote operation, the Post report said.

Obama still holds a clear lead over Romney in terms of backers' enthusiasm, as 51 percent of the Obama supporters back his candidacy "very enthusiastically," compared with 38 percent of Romney's, the poll found.