New political surveys show that President Barack Obama has a small lead over his Republican rival Mitt Romney, as the two candidates enter the final eight weeks of the U.S. presidential election campaign.

The Gallup and Rasmussen Reports polls Monday showed President Obama ahead of Mr. Romney by 5 percent following last week's Democratic National Convention.

More importantly, President Obama is leading in some key states, including Ohio, North Carolina and Colorado.

The two candidates had been virtually tied in surveys a week ago after the Republican National Convention.

Mr. Romney's campaign team said it is not worried about the current polls because it is natural that a candidate gets a boost in support after his party's convention.

Mr. Obama leads Mr. Romney 50 percent to 45 percent among likely voters in Ohio, according to a survey released Sunday by Public Policy Polling. The five-point lead in the midwestern state is the president's largest in that poll since early May.

But in North Carolina, where Democrats gathered last week to nominate the incumbent for a second term, a PPP survey Monday shows the president just slightly ahead of his Republican challenger, 49 to 48.

Mr. Obama's re-election campaign, for the first time in several months, narrowly raised more money in August than Mr. Romney's campaign.