President Barack Obama has stretched his lead over Republican nominee Mitt Romney in battleground states Ohio and Florida and retains a 12-point lead in Pennsylvania, according to a Quinnipiac University/New York Times/CBS poll released Wednesday.

The president is ahead 53 to 43 percent in Ohio and 53 to 44 percent in Florida, according to surveys of likely voters conducted Sept. 18-24. In Pennsylvania, Obama leads 54-42 percent.

Peter A. Brown, assistant director of the Quinnipiac University Polling Institute, attributed the swing in Obama's favor to negative media coverage of Romney over the past few weeks but said the Republican nominee still has time to reverse the president's lead.

"Gov. Mitt Romney had a bad week in the media and it shows in these key swing states," Brown said. "The furor over his 47 percent remark almost certainly is a major factor in the roughly double-digit leads President Barack Obama has in Florida, Ohio and Pennsylvania. The debates may be Romney's best chance to reverse the trend in his favor."

If national electorate models hold, Florida and Ohio will be crucial for Romney to reach the 270 Electoral College votes needed to best Obama on Election Day. According to the Quinnipiac University poll, Romney continues to struggle with female voters, who favor Obama by 19 percentage points in Florida, 25 percentage points in Ohio and 21 percentage points in Pennsylvania. The surveys in Ohio and Pennsylvania have a margin of error of plus or minus 2.9 percent and plus or minus 2.8 percent in Florida.

Other recent polls, however, show closer races in these battleground states. A Mason-Dixon survey unveiled Sunday and conducted Sept. 17-19 showed a statistical tie between Obama and Romney in Florida. According a recent Washington Post poll, Obama leads by 8 percentage points in Ohio and 4 percentage points in Florida.