US President Barack Obama has said he believes he deserves a second term in the White House.

美国总统奥巴马称，他相信自己能够连任下届总统。

His declaration, in an interview with NBC, came as a new poll showed his approval ratings moving past 50% for the first time since May 2011.

The ABC News/Washington Post survey also suggests Mr Obama would beat Republican front-runner Mitt¹ Romney.

Mr Romney and his rivals are now campaigning in Colorado and Minnesota after his weekend caucus²（核心会议） win in Nevada.

States across the US are currently holding nominating contests to pick a Republican nominee³ to challenge Mr Obama in November's general election.

Mr Obama's NBC interview was broadcast ahead of the Super Bowl, the most-watched TV event of the year.

It came two days after improved employment figures prompted analysts⁴ to suggest his prospects⁵ for securing four more years in the White House were improving.

"I deserve a second term, but I am not done," Mr Obama said. "We've created 3.7 million jobs in the last 23 months.

"We've created the most jobs since 2005, the most manufacturing jobs since 1990, but we're not finished.

"What I'm going to just keep on doing is plodding⁶ away, very persistent⁷. And you know what? One of the things about being president is you get better as time goes on."

Split decision

The ABC News/Washington Post poll - carried out over the end of last week and into the weekend - indicated that some of the positive economic data of the past few months could be filtering through to the electorate⁸（选民，选区） .

Asked directly to choose a president if an election were being held now, 51% of the 1,000 respondents chose Mr Obama, with Mr Romney on 45%.

Matched against former House of Representatives Speaker Newt Gingrich, who is running second in the Republican race, Mr Obama came out ahead by a wider margin⁹, 54% to 43%.

Mr Gingrich, as well as Ron Paul and Rick Santorum, has vowed¹⁰ to stay in the nomination¹¹ fight, despite seeing Mr Romney win 50% of the votes in the Nevada Republican caucuses¹² at the weekend.

Although his approval ratings are up, Mr Obama remains¹³ a polarising figure. Asked whether or not he should have a second term in office - but without being asked to choose between him and an alternative president - the respondents were split 49%-49%.