US President Barack Obama speaks at a campaign event at James Day Park in Parma, Ohio July 5, 2012. Obama is on a two-day campaign bus tour of Ohio and Pennsylvania. [Photo/Agencies]

WASHINGTON, July 5 - US President Barack Obama on Thursday kicked off a two-day campaign bus tour through battleground states of Ohio and Pennsylvania, during which he touted the work of his administration and attacked presumed Republican presidential nominee Mitt Romney.

Obama spent the first day of his tour in Ohio, making three stops in Maumee, Sandustky and Parma, all in northern manufacturing belt of the Midwestern US state. In a speech in Maumee, Obama celebrated the Supreme Court's ruling for upholding the healthcare reform, his signature domestic policy, saying the law is "here to stay."

But healthcare is not the major theme of his speech. Speaking at a museum not far from a Chrysler factory in Toledo that built Jeep Wrangler and Liberty, Obama claimed credit for Ohio's improving economy, especially the automobile industry.

"I refused to turn my back on communities like this one," said Obama under scorching sun. "And three years later, the American auto industry is coming roaring back. That Chrysler plant up the road bringing on another 1,100 employees to make the cars that the world wants to buy."

Obama also attacked Romney for his opposition against the auto bailout, noting Romney "said we should just let Detroit go bankrupt."

He also continued a line of attack that painted Romney's private sector experience as one that outsourced American jobs, saying "Governor Romney's experience has been in owning companies that were called 'pioneers' of outsourcing."

At the second stop in Sandusky, Obama added more personal touch to his speech, recounting his own family story to evoke the basic bargain that "if you work hard, you can make it," saying he is fighting for the middle class for a fair shot at success.

Obama's first bus tour in 2012 took place in areas where unemployment numbers were relatively low, but the tour could also carry risks as the new jobs number is set to be released on Friday, and he would have no choice but to address it.