WASHINGTON - US President Barack Obama on Saturday kicked off a tight-scheduled campaign tour in key battleground states to warm up for next week's Democratic National Convention in Charlotte, North Carolina.

Obama started his "Road to Charlotte" tour with a rally before 10,000 people in Iowa, touting his success in cutting taxes, expanding health care, delivering education assistance and bringing US troops back from decade-long wars.

US President Barack Obama shakes hands with people after arriving at Des Moines International Airport in Iowa Sept 1, 2012. [Photo/Agencies]

Obama rebutted the "It's Obama's fault" argument that had been frequently used by Republican presidential nominee Mitt Romney and his fellows during their party convention in Tampa, Florida over the last week.

"I will offer you what I believe is a better path forward - a path that grows this economy, creates more good jobs, strengthens the middle class," said Obama, highlighting his acceptance speech slated for next Thursday at the Democratic party's convention.

The four-day campaign tour included visits to Iowa, Colorado, Ohio, and Virginia, all of which are battleground swing states "we feel will play a pivotal role" in a close election, said Obama campaign spokeswoman Jen Psaki on Air Force One en route to the president's campaign rallies in Iowa.

She said the presidential race has been "pretty steady" to date and still "in a pretty similar place following the party's convention," which is usually believed to bump a candidate's support.

"We think it's going to be close to the end. That's why we have such an active schedule," said Psaki.

Obama's events will be sandwiched by a visit next Monday to the storm-damaged state of Louisiana, where Romney took a detour Friday, right after he accepted the party's nomination Thursday night.