MAUMEE, Ohio - President Barack Obama has heralded his first re-election campaign bus tour with a new trade blast at China and fresh accusations his White House foe Mitt Romney helped send US jobs abroad.
Obama set off through the bellwether state of Ohio on his sleek, black, armoured bus, touting his rescue of the US auto industry and contrasting his vision for the struggling middle-class with that of his rich Republican rival.
Before rolling into the Toledo area, home to General Motors and Daimler-Chrysler plants, Obama announced a new rebuke of China, a bogeyman in heartland America, over duties on $US3 billion ($F5.4billion) in US auto exports.
"Just this morning, my administration took a new action to hold China accountable for unfair trade practices that harm American auto makers," Obama told a sun-baked crowd seated before a barn draped in an American flag.