Washington: US President Barack Obama and his Republican challenger Mitt Romney remain locked closely in the race for the White House, according to two new polls released ahead of the Republican presidential convention starting on Monday.
A CNN/ORC International poll released on Friday found Obama attracted 49 percent of likely voters to Romney`s 47 percent, within the poll`s margin of error.
On the other hand, the first poll released by Fox News showed Romney one point ahead with 45 percent to Obama`s 44 percent.
In the CNN poll Obama led, 52 to 43, among a broader pool of registered voters including those less likely to vote -- consistent with CNN`s last poll in early August.
Historically, polls of likely voters tend to show slightly more favourable numbers for Republicans.
"This explains why the margin between President Obama and Mitt Romney is smaller among likely voters," CNN polling director Keating Holland explained.
"But it is a mistake to say that the race has tightened in the past few weeks, given the lack of movement in the results for registered voters," he said.
More than a third of registered Republicans -- 35 percent -- said they were extremely enthusiastic about the election, compared to 29 percent of registered Democrats.
The challenge for Romney at his convention, which starts on Monday in Tampa, Florida, is to boost his favourable ratings and re-establish the Republican brand nationwide, CNN said.
The CNN/ORC poll used live phone interviews August 22 and 23 to survey 924 registered voters, 719 of them likely voters, with a 3.5 percent margin of error.
According to a Fox News poll of likely voters, Romney has the edge among white Evangelical Christians (70-18 percent), white voters (53-36 percent), married voters (51-38 percent), men (48-40 percent) and seniors (50-41 percent).
Obama has the advantage among black voters (86-6 percent), women (48-42 percent), lower income households (53-35 percent), young voters (48-39 percent) and unmarried voters (55-34 percent).
Independents back Romney by 42-32 percent (one in four is undecided). Independents were vital to Obama`s 2008 victory, backing him over Republican John McCain by 52-44 percent (Fox News exit poll).
The Fox News poll is based on live phone interviews from August 19 to August 21 among 1,007 randomly-chosen likely voters nationwide.