Barack Obama used his speech to highlight his role in saving the US car industry from bankruptcy in 2009. Photograph: Chip Somodevilla/Getty Images
Barack Obama has used a tour of the swing state of Ohio to renew his claim that his Republican opponent, Mitt Romney, led the outsourcing of American jobs to India and China.
The assertion is controversial and has been largely discredited by independent fact-checking groups.
But Obama showed no sign of backing away from the claims on Thursday, telling an audience in Maumee, Ohio that Romney's executive experience was in "companies that were pioneers of outsourcing".
While Obama was still on his feet delivering the speech, the Romney campaign hit back, denouncing the claim as a "distortion" and saying there was no evidence that Romney, as head of Bain Capital, was responsible for sending jobs overseas.
Obama was speaking on the first day of a two-day bus tour of Ohio and Pennsylvania, two of three swing states – the other being Florida – that could determine November's White House election.
The president's speech came in advance of the publication on Friday of official jobs figures, the dominant issue of the campaign so far. Unemployment has been creeping down, but in recent months job growth has shown signs of slowing, a trend that could prove extremely damaging for Obama.