Mitt Romney, the presumptive Republican presidential nominee, has taken a narrow three per cent lead over United States President Barack Obama, who is seeking re-election, a national opinion poll has said.
Though the three per cent still falls under the margin of error, it assumes significance as Obama and Romney were tied at 46 per cent in the same poll conducted in April by the CBS News-The New York Times poll.
According to the survey, conducted May 11-13, 46 per cent of registered voters said they would vote for Romney, while 43 per cent said they would opt for Obama, the CBS news said.
"Romney's slight advantage remains within the poll's margin of error, which is plus or minus four percentage points," it noted.
The poll indicated that economy remains the top priority for the people, despite recent controversies surrounding issues like same-sex marriage, which Obama came out in support of last week.
Sixty-seven per cent of those surveyed by The New York Times and CBS News since the announcement said they thought that Obama had made it "mostly for political reasons", while 24 per cent said it was "mostly because he thinks it is right."
Independents were more likely to attribute it to politics, with nearly half of Democrats agreeing, the daily reported referring to the results of the survey.
"With less than six months until the election, Mr Obama remains in a tight race with Mr Romney," The New York Times said.
Obama's vulnerable standing in the poll came despite rising optimism about the economy, the daily said.
"About a third of voters said it was very or fairly good, the most since January 2008. More than a third said it was getting better, compared with a quarter who said it was getting worse," it said.
"Jobs and the economy remain by far the most dominant issue, with 62 per cent naming it their top priority and 19 per cent their second highest. By contrast, just 7 per cent chose same-sex marriage as the most important issue and 4 per cent as the second-most important," the daily said.