WASHINGTON - US President Barack Obama is seeing a surge in support among voters, with poll numbers released Tuesday suggesting his approval rating is nearing the 50 percent mark.

According to a national survey done by CNN/ORC International Poll, 49 percent of Americans approve of the job Obama is doing in the White House, up five points from last month, with 48 percent saying they disapprove, down six points from mid-November. The 49 percent approval rating is Obama's highest since May, when his number hit 54 percent after the killing of Osama bin Laden.

The rise of the president's popularity is in part attributed to the partisan battle over extending the payroll tax cut.

"President Barack Obama's approval rating appears to be fueled by dramatic gains among middle-income Americans," said CNN Polling Director Keating Holland. "The data suggest that the debate over the payroll tax is helping Obama's efforts to portray himself as the defender of the middle class."

The two parties have been fighting a bitter war over extending the popular tax cuts. After Senate approval of a long-awaited measure to extend the payroll tax cuts and federal jobless benefits for two months, the Republican-controlled House of Representatives on Tuesday scuttled it.

Obama, in a surprise visit to the White House press briefing room after the House vote, urged House Republicans to vote on the short-term Senate bill and avoid a tax hike for 160 million American workers at the start of next year.

The CNN poll was conducted by ORC International from Dec 16 to Dec 18, with 1,015 adult Americans questioned by telephone. The survey's overall sampling error is plus or minus three percentage points.